Wear and Osteolysis Basic Science

Question 1

Volumetric Wear

Answer 1

directly related to square of radius of head
V=Pie9 (rSquared) w
Therefore head size is most determiant factor is number of parcile generated

Question 2

UHMWPE

Answer 2

Less wear particles, smaller wear particles, less mechanical properties

Question 3

Osteoclast activation and Osteolysis

Answer 3

Via the RANKL Pathway

Question 4

Denosumab Inhibits?

Answer 4

RANKL- Therefore inhibits Osteoclastogeneisis

Question 5

Enteracept inhibits/Counteracts

Answer 5

TNF a (which is pro-inflammatory)

Question 6

Tocilizumab inhibits?

Answer 6

Monoclonal antibody to IL-6

Question 7

UHMWPE Mechanical Pitfalls

Answer 7

Decrease Ductility
Decreased Fracture Propagation Prevention
Decreased Tensile Strength

Question 8

Biologic Response to PE wear productes is directly proportional to ______

Answer 8

Number of particles

Question 9

N-Telopeptide breaker marker of What?

Answer 9

Type I Collagen

Question 10

Aseptic Loosening of Implants Thinks secreted by macrophages

Answer 10

IL-6, IL-1, PDGF, PGE2

Question 11

UHMWPE wear rates are independent of head size between sized ___ and ___

Answer 11

22–>46

Question 12

___ wear rate AND____ wear rate contribute to osteolysis

Answer 12

Liner and VOlumetric

Question 13

Wear Rates with increased risk of osteolysis ?

Answer 13

> 0.1mm/year

Question 14

Osteoprotegrin binds to what structure to decrased osteolysis ?

Answer 14

RANKL

Question 15

Acetabular Bone Loss Grading?

Answer 15

AAOS
I- Segmental
II Caavitary (volumetric
III: combined 
iV: pelvic discontinuity 
V: arthrodesis

Question 16

Acetabular Bone Lone Paprosky

Answer 16

I; Minimal deformity, intact rim
2A: Superior bone loss
2B- Superior lateral bone loss 
2C: Central bone loss
3A: Involving columbs
3B: pelvic Discontinuity

Question 17

MObile bearing desing of PE on tibial base plate does what

Answer 17

• decrease poly wear (theorectical) NOT proven
• Same survivorship
• increase spit out in flexion space

Question 18

Stand-alone revision acetabular liner replacement has high increased incidence of ?

Answer 18

post-op dislocation

Question 19

Contraindications for femoral head resurfacings?

Answer 19

femoral head cyst >1cm
Coxa Vara (poor outcomes)
Acetabular dysplasia or loss of bone stock

Question 20

What is the Kerbooul Angle?

Hip Osteonecrosis

Answer 20

• Measuring the necrotic angle wedge on AP and LAT and combining the two angle sums
  Low risk <190
  Mod Risk 190-240
  High Risk >240

Question 21

Ficat mod of Stienberg Classification

- Hip osteonecrois

Answer 21

o- normal Xray, Normal MR
I; norma xray, abdnormal MR (dark on t1)
II; cystic or scleoriss changes
III- crescent sign (subchondral collapse)
IV: femoral head flattening 
V: Narrowing of joint
VI: advnaced degen

Question 22

Vancouver Type b3 treatemnt
Younger?
Older?

Answer 22

young- Allograft composite replacement

Older: cemented segmental replacement, proximal femoral replacemnet

Question 23

What should normal Lateral Center Edge Angle be?

Answer 23

> 25

Question 24

What should vertical center edge angle be and on what view?

Answer 24

> 25

on False Profile view

Question 25

What shoulder the normal Tonnis agnle be?

Answer 25

<13

Question 26

What femoral alpha angles seen on lateral xray are suspicious for CAM lesion?

Answer 26

> 42 d

Question 27

Top three causes of of TKA failure?

Answer 27

1> aseptic loosening

2. Septic failure
3. Instability

Question 28

Anderson TKA femoral bone loss classificaiton

Answer 28

1
2A; loss on one femoral of tibial condyle
2B: Loss on both condyles
3 Massive loss- bulk allographfts,
cavitary defect <1cm cement, >1 cm sleeves, cones

Question 29

What mediator is found to be responsible in partical mediated osteolysis?

Answer 29

TNF-Alpha

releated to number no exacly size of particles

Question 30

Cross-Linking

Oxidation removal

Answer 30

• Radiation Gamma, inert air

- Heating, melting

Question 31

What type of allergy class is allergy to metal?

Answer 31

Type IV hypersensitivity RXN,

Question 32

What amount of acetabular component uncoverage is acceptable ?

Answer 32

< 30%

Question 33

Titanium tibial baseplate versus all poly

Answer 33

No difference in functional status

- poly version is cheaper

Question 34

Dose for HO radiation?

Answer 34

Preop within 24 hours
Post op within 72 hours
HAS TO BE 700cGY