SLIDE 1 Reading Assignment:
De Wall Malefijt et al., “The Actual Status of Acrylic Bone Cement in Total Hip Replacement,” Acta Orthop. Belg. 53: 52-58, 1987. Also, (re) read the Barich Ph.D. thesis section on fixturing for laboratory micromotion testing.
Homework Assignment:
Review the Davies et al. article and the Rimnac et al. article on the effects of cement centrifugation. Take a side in this controversy, and support your view by critical
- reasoning. Should PMMA be centrifuged? Write 2-3
pages, double-spaced 12 pt. Due Wed Oct 9th.
SLIDE 2
Biomechanics of Acrylic Cement Fixation
SLIDE 3
C – O* + C = C C = O O H H CH3 C – O – C – C* O CH3 O C = O CH3 H H O CH3 C – O – C – C C = O CH3 C = O H C – C
…
C = O C = O H C – C* C – C O H CH3 CH3 H H H CH3 CH3 O H H O O O CH3 CH3 CH3
Polymerization Reaction
SLIDE 4
Setting Time: 8.5 mins.
Property Changes Approaching Setting Time
SLIDE 5 Effect of Aging
Breaking Stress
SLIDE 6 Effect of Aging
Elastic Modulus
SLIDE 7
Calcar
Regions of High Cement Stress
SLIDE 8
Cement-Bone Interface
SLIDE 9
Beam Theory
Load Transmission through the Stem
SLIDE 10
Construct Stresses from Beam Theory
M: unit moment DM: medullary diam. DP: prosthesis diam.
SLIDE 11 FEA
Construct Stesses
SLIDE 12
Distribution of Bending Stresses
SLIDE 13
SLIDE 14
SLIDE 15
SLIDE 16
As Cut High Intensity Lavage
Cement Technique & Surface Preparation
SLIDE 17
As Cut
High Intensity Lavage
Cement Technique & Surface Preparation
SLIDE 18
Complete Contact
Cement-Bone Interface
Gap
SLIDE 19
Fatigue Test Specimen
SLIDE 20
Uncentrifuged Centrifuged
Simplex P
Cement Porosity
SLIDE 21
Maximum Initial Tensile Stress (MPa)
S-N Curves
SLIDE 22
Survival Probability
SLIDE 23
Survival Probability
SLIDE 24
Uniaxial Tensile Test
SLIDE 25
Endurance Limit
SLIDE 26 Compact Tensile Specimen
Fracture Toughness Test
SLIDE 27
Crack Propagation
SLIDE 28
Compact Tensile Specimen
SLIDE 29 Zimmer Simplex Palacos Gentimicin
Fracture Toughness Comparisons
SLIDE 30
Fatigue Crack Propagation
SLIDE 31
Gel Permeation Chromatography
Molecular Weight Distributions
SLIDE 32
Contraction upon Setting
SLIDE 33
Fracture around Particles
SLIDE 34
Fracture through Particles
SLIDE 35
Average Molecular Weights
