Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

ME498 Final > Bone implants > Flashcards

Bone implants Flashcards

1
Q

What are materials used in the body called?

A

Biomaterials

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the two classes of biomaterials?

A

Bio-inert: joint replacements, metals and polymers, fixation plates

Bio-active: materials which resorb or enhance bone growth, tissue-engineered scaffolds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does biocompatible mean?

A

Does not damage or impair the function of the implanted materials or the tissues of the musculoskeletal system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is UHMWPE?

A

Ultra-High Molecular Weight Polyethylene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the elastic modulus of UHMWPE?

A

N/A - non-linear material

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are stainless steels typically used for?

A

Bone fracture plates
Screws
Hip nails
Joint replacements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are cobalt chromium alloys used for?

A

Bone plates
Joint replacements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is titanium typically used for?

A

Bone plates
Joint replacements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is UHMWPE used for?

A

Bearing material

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is Polymethyl Methacrylate used for?

A

Fix components to bone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the advantages of stainless steels?

A
  • Good balance of strength, ductility and fatigue performance
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the disadvantages of stainless steels?

A

-Corrosion/Pitting (address by including Cr and Mo)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the benefits of cobalt chromium alloys?

A
  • Range of mechanical properties for varied purposes
  • Resistant to corrosion and fatigue failure
  • Ductile
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the disadvantages of cobalt chromium alloys?

A
  • made via casting, leading to unevenly distributed carbides (addresses by forging)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the benefit of UHMWPE?

A
  • High impact strength
  • Adjustable props via radiation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the disadvantages of UHMWPE?

A
  • Excessive crosslinking lowers ductility
  • Needs controlled environment for cross linking
17
Q

What are the benefits and drawbacks of screw fixation?

A

(+): Simple, Minimally invasive

(-): Challenging to align fracture surfaces

18
Q

What are the benefits of plates, rods and nails?

A

(+): can resist bending, plates can be guided for tapping bone

(-): could result in stress shielding

19
Q

What are the benefits of external fixators?

A

(+): can be adjusted to place more load on bone

(-): cumbersome for patient, risk of infection

20
Q

What are two considerations when designing fixation devices?

A

Mechanical behaviour of the device: crucial if it must carry all load

Mechanics of the bone-fixator structure: crucial to prevent stress shielding

21
Q

What is the goal of a joint replacement?

A

Replicate the native condition as much as possible

22
Q

What are the two classes of joint replacements?

A

Replacements of the articulate surface (Acetabular cups, femoral and tibial components of TKA): load transferred to underlying trab bone

Replacement of the articular surface and substructure of the bone

23
Q

What is PMMA Fixation vs Cementless Fixation?

A

PMMA: at the cement-bone interface, pmma interlocks with the roughness of bone. At bone-implant, pmma weakly adheres to metal and rigid fixation by mechanical interlocks

Cementless: coat prosthesis with porous mat’l to encourage bony ingrowth

24
Q

What is the typical lifespan of an implant?

A

10-15 years

25
Q

Why is fatigue of implants an important consideration in implant design?

A

Bone defects will repair themselves but damage to the implant will not

26
Q

Why is stress shielding an issue?

A

If most of the load is carried by the implant, bone loss will occur in some regions. This will reduce the strength of bone, potentially leading to fracture and more load on the implant increases it’s chance of failure

27
Q

What is osteolysis?

A

If enough debris is created between articulating surfaces, WBCs may attack the bone as a response to foreign debris

28
Q

What are the pros and cons of survival analyses?

A

(+): identifies specific design which offers best performance

(-): does not identify specific design features

29
Q

What are the pros and cons of retrieval analyses at revision or autopsy?

A

(+): best source for evaluating in vivo performance

(-): challenging to coordinate retrieval

30
Q

What are the pros and cons of long term follow up studies?

A

(+): acquire info about specific design

(-): expensive, subjective

31
Q

What are the pros and cons of small-scale in vivo studies?

A

(+): squire info about specific design

(-): limited sample size, FDA approval

32
Q

What are the pros and cons of ex vivo cadaveric studies?

A

(+): acquire info about specific design

(-): expensive, specialized knowledge and equipment

33
Q

What are the pros and cons of preclinical in vivo animal studies?

A

(+): acquire info about specific design

(-): may not reflect human condition

34
Q

What are the pros and cons of in silico subject specific FE modelling?

A

(+): can evaluate multiple designs

(-): model accuracy is questionable, specialized knowledge and software, time consuming

ME498 Final (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions