Ultra high molecular weight polyethylene (UHMWPE, or ultra high), a frequently used material in orthopedic joint replacements, is often the cause of joint failure due to wear, fatigue, or fracture. These mechanical failures have been related to ultra high's strength and stiffness, and ultimately to the underlying microstructure, in previous experimental studies. Ultra high's semicrystalline microstructure consists of about 50% crystalline lamellae and 50% amorphous regions. Through common processing treatments, lamellar percentage and size can be altered, producing a range of mechanical responses. However, in the orthopedic field the basic material properties of the two microstructural phases are not typically studied independently, and their manipulation is not computationally optimized to produce desired mechanical properties. Therefore, the purpose of this study is to: (1) develop a 2D linear elastic finite element model of actual ultra high microstructure and fit the mechanical properties of the microstructural phases to experimental data and (2) systematically alter the dimensions of lamellae in the model to begin to explore optimizing the bulk stiffness while decreasing localized stress. The results show that a 2D finite element model can be built from a scanning electron micrograph of real ultra high lamellar microstructure, and that linear elastic constants can be fit to experimental results from those same ultra high formulations. Upon altering idealized lamellae dimensions, we found that bulk stiffness decreases as the width and length of lamellae increase. We also found that maximum localized Von Mises stress increases as the width of the lamellae decrease and as the length and aspect ratio of the lamellae increase. Our approach of combining finite element modeling based on scanning electron micrographs with experimental results from those same ultra high formulations and then using the models to computationally alter microstructural dimensions and properties could advance our understanding of how microstructure affects bulk mechanical properties. This advanced understanding could allow for the engineering of next-generation ultra high microstructures to optimize mechanical behavior and increase device longevity.

References

References
1.
Kurtz
,
S.
,
Mowat
,
F.
,
Ong
,
K.
,
Chan
,
N.
,
Lau
,
E.
, and
Halpern
,
M.
,
2005
, “
Prevalence of Primary and Revision Total Hip and Knee Arthroplasty in the United States From 1990 Through 2002
,”
J. Bone Joint Surg. Am.
,
87
(
7
), pp.
1487
1497
.10.2106/JBJS.D.02441
2.
Kurtz
,
S.
,
Ong
,
K.
,
Lau
,
E.
,
Mowat
,
F.
, and
Halpern
,
M.
,
2007a
, “
Projections of Primary and Revision Hip and Knee Arthroplasty in the United States From 2005 to 2030
,”
J. Bone Joint Surg. Am.
,
89
(
4
), pp.
780
785
.10.2106/JBJS.F.00222
3.
Kurtz
,
S. M.
,
Ong
,
K. L.
,
Schmier
,
J.
,
Mowat
,
F.
,
Saleh
,
K.
,
Dybvik
,
E.
,
Kärrholm
,
J.
,
Garellick
,
G.
,
Havelin
,
L. I.
,
Furnes
,
O.
,
Malchau
,
H.
, and
Lau
,
E.
,
2007b
, “
Future Clinical and Economic Impact of Revision Total Hip and Knee Arthroplasty
,”
J. Bone Joint Surg. Am.
,
89
(
3
), pp.
144
151
.10.2106/JBJS.G.00587
4.
Ong
,
K. L.
,
Mowat
,
F. S.
,
Chan
,
N.
,
Lau
,
E.
,
Halpern
,
M. T.
, and
Kurt
,
S. M.
,
2006
, “
Economic Burden of Revision Hip and Knee Arthroplasty in Medicare Enrollees
,”
Clin. Orthop. Relat. Res.
,
446
, pp.
22
28
.10.1097/01.blo.0000214439.95268.59
5.
Bozic
,
K. J.
,
Kurtz
,
S. M.
,
Lau
,
E.
,
Ong
,
K.
,
Vail
,
T. P.
, and
Berry
D. J.
,
2009
, “
The Epidemiology of Bearing Surface Usage in Total Hip Arthroplasty in the United States
,”
J. Bone Joint Surg. Am.
,
91
(
7
), pp.
1614
1620
.10.2106/JBJS.H.01220
6.
Furmanski
,
J.
,
Anderson
,
M.
,
Bal
,
S.
,
Greenwald
,
A. S.
,
Halley
,
D.
,
Penenberg
,
B.
,
Ries
,
M. D.
, and
Pruitt
,
L. A.
,
2009
, “
Clinical Fracture of Cross-Linked UHMWPE Acetabular Liners
,”
Biomaterials
,
30
(
29
), pp.
5572
5582
.10.1016/j.biomaterials.2009.07.013
7.
Ries
,
M. D.
, and
Pruitt
,
L.
,
2005
, “
Effect of Cross-Linking on the Microstructure and Mechanical Properties of Ultra-High Molecular Weight Polyethylene
,”
Clin. Orthop. Relat. Res.
,
440
, pp.
149
156
.10.1097/01.blo.0000185310.59202.e5
8.
Atwood
,
S. A.
,
Van Citters
,
D. W.
,
Patten
,
E. W.
,
Furmanski
,
J.
,
Ries
,
M. D.
, and
Pruitt
,
L. A.
,
2010
, “
Tradeoffs Amongst Fatigue, Wear, and Oxidation Resistance of Cross-Linked Ultra-High Molecular Weight Polyethylene
,”
J. Mech. Behav. Biomed. Mat.
,
4
(
11
), pp.
1033
1045
.10.1016/j.jmbbm.2011.03.012
9.
Medel
,
F. J.
,
Peña
,
P.
,
Cegoñino
,
J.
,
Gomez-Barrena
,
E.
, and
Puertolas
,
J. A.
,
2007
, “
Comparative Fatigue Behavior and Toughness of Remelted and Annealed Highly Crosslinked Polyethylenes
,”
J. Biomed. Mater. B
,
83
(
2
), pp.
380
390
.10.1002/jbm.b.30807
10.
Simis
,
K. S.
,
Bistolfi
,
A.
,
Bellare
,
A.
, and
Pruitt
L. A.
,
2006
, “
The Combined Effects of Crosslinking and High Crystallinity on the Microstructural and Mechanical Properties of Ultra-High Molecular Weight Polyethylene
,”
Biomaterials
,
27
(
9
), pp.
1688
1694
.10.1016/j.biomaterials.2005.09.033
11.
Edidin
,
A. A.
,
Pruitt
,
L.
, and
Jewett
C. W.
, Crane, D. J., Roberts, D., and Kurtz, S. M.,
1999
, “
Plasticity-Induced Damage Layer is a Precursor to Wear in Radiation-Cross-Linked UHMWPE Acetabular Components for Total Hip Replacement
,”
J. Arthroplasty
,
14
(
5
), pp.
616
627
.10.1016/S0883-5403(99)90086-4
12.
Kurtz
,
S. M.
,
Foulds
,
J. R.
,
Jewett
,
C. W.
,
Srivastav
,
S.
, and
Edidin
,
A. A.
,
1997
, “
Validation of a Small Punch Testing Technique to Characterize the Mechanical Behaviour of Ultra-High-Molecular-Weight Polyethylene
,”
Biomaterials
,
18
(
24
), pp.
1659
1663
.10.1016/S0142-9612(97)00124-5
13.
Saikko
,
V.
, and
Ahlroos
,
T.
,
2000
, “
Wear Simulation of UHMWPE for Total Hip Replacement With a Multidirectional Motion Pin-on-Disk Device: Effects of Counterface Material, Contact Area, and Lubricant
,”
J. Biomed. Mat. Res.
,
49
(
2
), pp.
147
154
.10.1002/(SICI)1097-4636(200002)49:2<147::AID-JBM1>3.0.CO;2-H
14.
Van Citters
,
D. W.
,
Kennedy
,
F. E.
, and
Collier
J. P.
,
2007
, “
Rolling Sliding Wear of UHMWPE for Knee Bearing Applications
,”
Wear
,
263
, pp.
1087
1094
.10.1016/j.wear.2006.11.038
15.
Baker
,
D. A.
,
Bellare
,
A.
, and
Pruitt
,
L.
,
2003
, “
The Effects of Degree of Crosslinking on the Fatigue Crack Initiation and Propagation Resistance of Orthopedic Grade Polyethylene
,”
J. Biomed. Mat. A
,
66
, pp.
146
154
.10.1002/jbm.a.10606
16.
Essner
,
A.
,
Schmidig
,
G.
, and
Wang
,
A.
,
2005
, “
The Clinical Relevance of Hip Joint Simulator Testing: In Vitro and In Vivo Comparisons
,”
Wear
,
259
, pp.
882
886
.10.1016/j.wear.2005.02.105
17.
Muratoglu
,
O. K.
,
Bragdon
,
C. R.
,
Jasty
,
M.
,
O'Connor
,
D. O.
,
Von Knoch
,
R. S.
, and
Harris
,
W. H.
,
2004
, “
Knee-Simulator Testing of Conventional and Cross-Linked Polyethylene Tibial Inserts
,”
J. Arthroplasty
,
19
(
7
), pp.
887
897
.10.1016/j.arth.2004.03.019
18.
Sutula
,
L. C.
,
Collier
,
J. P.
,
Saum
,
K. A.
,
Currier
,
B. H.
,
Currier
,
J. H.
,
Sanford
,
W. M.
,
Mayor
,
M. B.
,
Wooding
,
R. E.
,
Sperling
,
D. K.
,
Williams
,
I. R.
,
Kasprzak
,
D. J.
, and
Surprenant
,
V. A.
,
1995
, “
Impact of Sterilization on Clinical Performance of Polyethylene in the Hip
,”
Clin. Orthop. Relat. Res.
,
319
, pp.
28
40
.10.1097/00003086-199510000-00004
19.
Collier
,
J. P.
,
Bargmann
,
L. S.
,
Currier
,
B. H.
,
Mayor
,
M. B.
,
Currier
,
J. H.
, and
Bargmann
,
B. C.
,
1998
, “
An Analysis of Hylamer and Polyethylene Bearings From Retrieved Acetabular Components
,”
Orthopedics
,
21
(
8
), pp.
865
871
.
20.
Currier
,
B. H.
,
Currier
,
J. H.
,
Mayor
,
M. B.
,
Lyford
,
K. A.
,
Collier
,
J. P.
, and
Van Citters
,
D. W.
,
2007
, “
Evaluation of Oxidation and Fatigue Damage of Retrieved Crossfire Polyethylene Acetabular Cups
,”
J. Bone Joint Surg. Am.
,
89
, pp.
2023
2029
.10.2106/JBJS.F.00336
21.
Tai Te
Wu
,
1966
, “
The Effect of Inclusion Shape on the Elastic Moduli of a Two-Phase Material
,”
Int. J. Solid. Struct.
,
2
(
1
), pp.
1
8
.10.1016/0020-7683(66)90002-3
22.
Ahmed
,
S.
, and
Jones
,
F. R.
,
1990
, “
A Review of Particulate Reinforcement Theories for Polymer Composites
,”
J. Mat. Sci.
,
25
(
12
), pp.
4933
4942
.10.1007/BF00580110
23.
Lee
,
B. J.
,
Parks
,
D. M.
, and
Ahzi
,
S.
,
1993
, “
Micromechanical Modeling of Large Plastic Deformation and Texture Evolution in Semi-Crystalline Polymers
,”
J. Mech. Phy. Solids
,
41
(
10
), pp.
1651
1687
.10.1016/0022-5096(93)90018-B
24.
Bédoui
,
F.
,
Diani
,
J.
,
Régnier
,
G.
, and
Seiler
,
W.
,
2006
, “
Micromechanical Modeling of Isotropic Elastic Behavior of Semicrystalline Polymers
,”
Acta Mater.
,
54
(
6
), pp.
1513
1523
.10.1016/j.actamat.2005.11.028
25.
van Dommelen
,
J. A. W.
,
Parks
,
D. M.
,
Boyce
,
M. C.
,
Brekelmans
,
W. A. M.
, and
Baaijens
,
F. P. T.
,
2003
, “
Micromechanical Modeling of the Elasto-Viscoplastic Behavior of Semi-Crystalline Polymers
,”
J. Mech. Phy. Solids
,
51
(
3
), pp.
519
541
.10.1016/S0022-5096(02)00063-7
26.
van Dommelen
,
J. A. W.
,
Schrauwen
,
B. A. G.
,
Van Breemen
,
L. C. A.
, and
Govaert
,
L. E.
,
2004
, “
Micromechanical Modeling of the Tensile Behavior of Oriented Polyethylene
,”
J. Polym. Sci. B Polym. Phys.
,
42
, pp.
2983
2994
.10.1002/polb.20164
27.
van Dommelen
,
J. A. W.
,
Brekelmans
,
W. A. M.
, and
Baaijens
,
F. P. T.
,
2003
, “
Micromechanical Modeling of Particle-Toughening of Polymers by Locally Induced Anisotropy
,”
Mech. Mat.
,
35
(
9
), pp.
845
863
.10.1016/S0167-6636(02)00307-1
28.
Lin
,
L.
, and
Argon
,
A. S.
,
1994
, “
Structure and Plastic Deformation of Polyethylene
,”
J. Mat. Sci.
,
29
, pp.
294
323
.10.1007/BF01162485
29.
Farrar
,
D. F.
, and
Brain
,
A. A.
,
1997
, “
The Microstructure of Ultra-High Molecular Weight Polyethylene Used in Total Joint Replacements
,”
Biomaterials
,
18
(
24
), pp.
1677
1685
.10.1016/S0142-9612(97)00143-9
30.
Bergstrom
,
J.
,
Kurtz
,
S.
,
Rimnac
,
C.
, and
Edidin
,
A.
,
2002
, “
Constitutive Modeling of Ultra-High Molecular Weight Polyethylene Under Large-Deformation and Cyclic Loading Conditions
,”
Biomaterials
,
23
, pp.
2329
2343
.10.1016/S0142-9612(01)00367-2
31.
Bergstrom
,
J.
,
Rimnac
,
C.
, and
Kurtz
,
S.
,
2003
, “
Prediction of Multiaxial Mechanical Behavior for Conventional and Highly Crosslinked UHMWPE Using a Hybrid Constitutive Model
,”
Biomaterials
,
24
, pp.
1365
1380
.10.1016/S0142-9612(02)00514-8
32.
Bergstrom
,
J.
,
Rimnac
,
C.
, and
Kurtz
,
S.
,
2004
, “
An Augmented Hybrid Constitutive Model for Simulation of Unloading and Cyclic Loading Behavior of Conventional and Highly Crosslinked UHMWPE
,”
Biomaterials
,
25
, pp.
2171
2178
.10.1016/j.biomaterials.2003.08.065
33.
Bergstrom
,
J. S.
, and
Bischoff
,
J. E.
,
2010
, “
An Advanced Thermomechanical Constitutive Model for UHMWPE
,”
Int. J. Struct. Change Solid.
,
2
, pp.
31
39
.
34.
Olley
,
R.
, and
Basset
,
D.
,
1977
, “
Molecular-Conformations in Polyethylene After Recrystallization or Annealing at High Pressures
,”
J. Polym. Sci. B
,
15
(
6
), pp.
1011
1027
.10.1002/pol.1977.180150608
35.
Shi
,
W.
,
Dong
,
H.
, and
Bell
,
T.
,
2000
, “
Tribological Behaviour and Microscopic Wear Mechanisms of UHMWPE Sliding Against Thermal Oxidation-Treated Ti6Al4V
,”
Mat. Sci. Eng. A
,
291
(
1–2
), pp.
27
36
.10.1016/S0921-5093(00)00972-2
36.
Keller
,
T. F.
,
Engelhardt
,
H.
,
Adam
,
P.
,
Galetz
,
M. C.
,
Glatzel
,
U.
, and
Jandt
,
K. D.
,
2011
, “
Near-Surface Microstructural Reorganization of UHMWPE Under Cyclic Load—A Pilot Study
,”
Adv. Eng. Mater.
,
13
, pp.
476
482
.10.1002/adem.201180058
37.
Mizrahi
,
J.
,
Silva
,
M. J.
,
Keaveny
,
T. M.
,
Edwards
,
W. T.
, and
Hayes
,
W. C.
,
1993
, “
Finite-Element Stress Analysis of the Normal and Osteoporotic Lumbar Vertebral Body
,”
Spine
,
18
, pp.
2088
2096
.10.1097/00007632-199310001-00028
38.
Silva
,
M. J.
,
Keaveny
,
T. M.
, and
Hayes
,
W. C.
,
1998
, “
Computed Tomography-Based Finite Element Analysis Predicts Failure Loads and Fracture Patterns for Vertebral Sections
,”
J. Ortho. Res.
,
16
, pp.
300
308
.10.1002/jor.1100160305
39.
Niebur
,
G. L.
,
Feldstein
,
M. J.
,
Yuen
,
J. C.
,
Chen
,
T. J.
, and
Keaveny
,
T. M.
,
2000
, “
High-Resolution Finite Element Models With Tissue Strength Asymmetry Accurately Predict Failure of Trabecular Bone
,”
J. Biomech.
,
33
, pp.
1575
1583
.10.1016/S0021-9290(00)00149-4
40.
Wang
,
X.
,
Sanyal
,
A.
,
Cawthon
,
P. M.
,
Palermo
,
L.
,
Jekir
,
M.
,
Christensen
,
J.
,
Ensrud
,
K. E.
,
Cummings
,
S. R.
,
Orwoll
,
E.
,
Black
,
D. M.
, and
Keaveny
,
T. M.
,
2012
, “
Prediction of New Clinical Vertebral Fractures in Elderly Men Using Finite Element Analysis of CT Scans
,”
J. Bone Mineral Res.
,
27
(
4
), pp.
808
816
.10.1002/jbmr.1539
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