UHMWPE Biomaterials Handbook (eBook)

Front Cover 1
UHMWPE Biomaterials Handbook: Ultra-High Molecular Weight Polyethylene in Total Joint Replacement and Medical Devices 4
Copyright Page 5
Contents 8
Dedication 6
Foreword 18
Contributors 20
Chapter 1. A Primer on UHMWPE 22
1.1 Introduction 22
1.2 What is a Polymer? 23
1.3 What is Polyethylene? 23
1.4 Crystallinity 25
1.5 Thermal Transitions 25
1.6 Overview of the Handbook 26
References 27
Chapter 2. From Ethylene Gas to UHMWPE Component: The Process of Producing Orthopedic Implants 28
2.1 Introduction 28
2.2 Polymerization: from Ethylene Gas to UHMWPE Powder 29
2.2.1. GUR Resins 30
2.2.2. 1900 Resins 31
2.2.3. Molecular Weight 31
2.2.4. GUR versus 1900 Resin 31
2.2.5. Calcium Stearate 32
2.2.6. DSM Resin 33
2.3 Conversion: from UHMWPE Powder to Consolidated Form 33
2.3.1 Compression Molding of UHMWPE 34
2.3.2 Ram Extrusion of UHMWPE 35
2.3.3 Hot Isostatic Pressing of ArCom UHMWPE 35
2.3.4 Direct Compression Molding of UHMWPE 35
2.3.5 ArCom 37
2.3.6 Properties of Extruded versus Molded UHMWPE 37
2.4 Machining: from Consolidated Form to Implant 38
2.5 Conclusion 39
References 39
Chapter 3. Packaging and Sterilization of UHMWPE 42
3.1 Introduction 42
3.2 Gamma Sterilization in Air 43
3.3 Gamma Sterilization in Barrier Packaging 44
3.4 Ethylene Oxide Gas Sterilization 46
3.5 Gas Plasma Sterilization 47
3.6 The Torino Survey of Contemporary Orthopedic Packaging 47
3.7 Shelf Life of UHMWPE Components for TJR 49
3.8 Overview of Current Trends 50
3.9 Acknowledgments 50
References 50
Chapter 4. The Origins of UHMWPE in Total Hip Arthroplasty 52
4.1 Introduction and Timeline 52
4.2 The Origins of a Gold Standard (1958 to 1982) 53
4.3 Charnley's First Hip Arthroplasty Design with PTFE (1958) 54
4.4 Implant Fixation with Pink Dental Acrylic Cement (1958 to 1966) 54
4.5 Interim Hip Arthroplasty Designs with PTFE (1958 to 1960) 54
4.6 Final Hip Arthroplasty Design with PTFE (1960 to 1962) 55
4.7 Implant Fabrication at Wrightington 56
4.8 The First Wear Tester 57
4.9 Searching to Replace PTFE 58
4.10 UHMWPE Arrives at Wrightington 59
4.11 Implant Sterilization Procedures at Wrightington 59
4.12 Summary 61
4.13 Acknowledgments 61
References 62
Chapter 5. The Clinical Performance of UHMWPE in Hip Replacements 64
5.1 Introduction 64
5.2 Joint Replacements do not Last Forever 65
5.3 Range of Clinical Wear Performance in Cemented Acetabular Components 66
5.4 Wear versus Wear Rate of Hip Replacements 67
5.5 Comparing Wear Rates Between Different Clinical Studies 68
5.6 Comparison of Wear Rates in Clinical and Retrieval Studies 70
5.7 Current Methods for Measuring Clinical Wear in THA 70
5.8 Range of Clinical Wear Performance in Modular Acetabular Components 72
5.9 Conclusion 72
5.10 Acknowledgments 73
References 73
Chapter 6. Contemporary Total Hip Arthroplasty: Hard-on-Hard Bearings and Highly Crosslinked UHMWPE 76
6.1 Introduction 76
6.2 Metal-on-Metal Alternative Hip Bearings 78
6.2.1 Historical Overview of Metal-on-Metal 79
6.2.2 Contemporary (Second Generation) Metal-on-Metal Hip Designs 80
6.2.3 Metal-on-Metal Hip Resurfacing 81
6.2.4 Potential Biological Risks Associated with MOM Joints 82
6.3 Ceramics in hip arthroplasty 82
6.3.1 Historical Overview of Ceramics in THA 83
6.3.2 Ceramic Biomaterials for Hip Arthroplasty 83
6.3.3 Ceramic-on-UHMWPE 87
6.3.4 Contemporary Ceramic-on-Ceramic Hip Implants 89
6.3.5 Differential Hardness Bearings: Ceramic-on-Metal 90
6.3.6 Wear Mechanisms in Ceramic Bearings 90
6.3.7 In Vivo Fracture Risk of Ceramic Components for THA 91
6.4 Noise and Squeaking from Hard-on-Hard Bearings 93
6.5 Highly-crosslinked UHMWPE 93
6.5.1 Historical Clinical Experience with Highly Crosslinked UHMWPE 93
6.5.2 First-Generation Highly Crosslinked UHMWPE 93
6.5.3 Second-Generation Highly Crosslinked UHMWPE 95
6.6 Summary 95
References 96
Chapter 7. The Origins and Adaptations of UHMWPE for Knee Replacements 102
7.1 Introduction 102
7.2 Frank Gunston and the Wrightington Connection to TKA 104
7.3 Polycentric Knee Arthroplasty 106
7.4 Unicondylar Polycentric Knee Arthroplasty 107
7.5 Bicondylar Total Knee Arthroplasty 108
7.5.1 Cruciate Sparing Bicondylar Prostheses 108
7.5.2 The Total Condylar Knee 110
7.6 Patello-femoral Arthroplasty 112
7.7 Uhmwpe with Metal Backing 113
7.7.1 Fixed Bearing TKA 114
7.7.2 Mobile Bearing TKA 114
7.8 Conclusion 115
7.9 Acknowledgments 115
References 115
Chapter 8. The Clinical Performance of UHMWPE in Knee Replacements 118
8.1 Introduction 118
8.2 Biomechanics of Total Knee Arthroplasty 119
8.2.1 Anatomical Considerations 119
8.2.2 Knee Joint Loading 119
8.2.3 Stresses in UHMWPE Tibial and Patellar Components for TKR 121
8.3 Clinical Performance of UHMWPE in Knee Arthroplasty 123
8.3.1 Survivorship of Knee Arthroplasty 123
8.3.2 Reasons for Knee Arthroplasty Revision Surgery 124
8.3.3 Articulating Surface Damage Modes 126
8.4 Osteolysis and Wear in TKA 128
8.4.1 Incidence and Significance of Osteolysis in TKA 128
8.4.2 Methods to Assess In Vivo Wear in TKA 129
8.4.3 Backside Wear 133
8.4.4 Damage to Posts in PS Tibial Components 133
8.5 Alternatives to Conventional UHMWPE in TKA 134
8.5.1 Ceramic Bearings in TKA 134
8.5.2 Highly Crosslinked UHMWPE in TKA 135
Summary 135
Acknowledgments 135
References 136
Chapter 9. The Clinical Performance of UHMWPE in Shoulder Replacements 138
9.1 Introduction 138
9.2 The Shoulder Joint 138
9.3 Shoulder Replacement 139
9.3.1 Procedures 139
9.3.2 Patient Population 140
9.3.3 History 141
9.4 Biomechanics of Total Shoulder Replacement 142
9.5 Contemporary Total Shoulder Replacements 143
9.6 Clinical Performance of Total Shoulder Arthroplasty 147
9.6.1 Overall Clinical Success Rates 147
9.6.2 Loosening 148
9.6.3 Wear 149
9.7 Controversies in Shoulder Replacement 151
9.8 Future Directions in Total Shoulder Arthroplasty 152
9.8.1 Design 152
9.8.2 Materials 152
9.9 Conclusion 153
9.10 Acknowledgments 153
References 153
Chapter 10. The Clinical Performance of UHMWPE in Elbow Replacements 158
10.1 Introduction 158
10.2 Anatomy of the Elbow 158
10.2.1 Osteoarticular Anatomy 158
10.2.2 Soft Tissue Anatomy 160
10.2.3 Muscular Anatomy 160
10.3 Elbow Biomechanics 162
10.3.1 Kinematics 162
10.3.2 Joint Loading 162
10.4 Implant Design 162
10.4.1 Historical Context 162
10.4.2 Contemporary Designs 163
10.5 Osteolysis and Wear 170
10.6 Conclusion 172
10.7 Acknowledgments 172
References 172
Chapter 11. Applications of UHMWPE in Total Ankle Replacements 174
11.1 Introduction 174
11.2 Anatomy 175
11.3 Ankle Biomechanics 175
11.4 Total Ankle Replacement Design 177
11.4.1 Early Designs 177
11.4.2 Results of Early Designs 179
11.4.3 Contemporary Designs 179
11.5 UHMWPE Loading and Wear in Total Ankle Replacements 186
11.6 Complications and Retrieval Analysis 187
11.7 Conclusion 188
11.8 Acknowledgments 188
References 188
Chapter 12. The Clinical Performance of UHMWPE in the Spine 192
12.1 Introduction 192
12.2 The CHARITÉ Artificial Disc 193
12.2.1 SB CHARITÉ I and II 194
12.2.2 SB CHARITÉ III 194
12.2.3 Recent Generations of the CHARITÉ Artificial Disc 196
12.2.4 Bioengineering Studies of the CHARITÉ 196
12.2.5 Controversies Surrounding the CHARITÉ Artificial Disc 198
12.2.6 The Legacy of the CHARITÉ Artificial Disc 198
12.3 Lumbar Disc Arthroplasty 199
12.3.1 ProDisc-L 201
12.3.2 Mobidisc 204
12.3.3 Activ-L 205
12.4 Cervical Disc Arthroplasty 205
12.4.1 ProDisc-C 207
12.4.2 PCM 207
12.4.3 Mobi-C 209
12.4.4 Activ-C 209
12.4.5 Discover 209
12.5 Wear and In Vivo Degradation of UHMWPE in the Spine 209
12.6 Alternatives to UHMWPE in Disc Replacement 212
12.7 Many Unanswered Questions Remain 213
12.8 Acknowledgments 214
References 214
Chapter 13. Highly Crosslinked and Melted UHMWPE 218
13.1 Introduction 218
13.2 Radiation Crosslinking 219
13.3 Irradiation and Melting 219
13.4 Effect of Radiation Dose, Melting, and Irradiation Temperature on UHMWPE Properties 220
13.5 Effect of Crosslinking on Fatigue Resistance 221
13.6 Optimum Radiation Dose 222
13.7 Hip Simulator Data 222
13.8 Knee Simulator Data 222
13.9 Clinical Follow-up Studies 223
13.10 In vivo Changes: Explants 223
13.11 Conclusion 224
References 224
Chapter 14. Highly Crosslinked and Annealed UHMWPE 226
14.1 Introduction 226
14.2 Development of Duration Stabilized UHMWPE 226
14.2.1 The Duration Process 227
14.2.2 Properties of Duration Stabilized UHMWPE 227
14.2.3 Clinical Studies 228
14.2.4 Summary 228
14.3 Crossfire 228
14.3.1 Crossfire Process 229
14.3.2 Properties 229
14.3.3 Clinical Studies 230
14.3.4 Crossfire Retrievals 231
14.3.5 Summary 233
14.4 X3: Sequentially Irradiated and Annealed UHMWPE 233
14.4.1 Sequential Crosslinking Process 233
14.4.2 X3 Properties 234
14.4.3 X3 Clinical Studies 237
14.4.4 X3 Retrievals 237
14.4.5 X3 Summary 237
14.5 Conclusion 238
References 238
Chapter 15. Highly Crosslinked UHMWPE Doped with Vitamin E 242
15.1 Introduction 242
15.2 Function of Vitamin E 243
15.3 Diffusion of Vitamin E in Crosslinked UHMWPE 244
15.4 Wear 245
15.4.1 Hip 245
15.4.2 Knee 247
15.5 Mechanical and Fatigue Properties 247
15.5.1 Adverse Conditions 248
15.6 Oxidative stability 249
15.7 Biocompatibility 250
15.7.1 Vitamin E Toxicity in Clinical Studies with Large Cohorts and Comorbidities 251
15.7.2 Toxic Effects of High Dose of Vitamin E in Patients on Warfarin Therapy (Two Cases) 252
15.7.3 Plasma and Tissue Levels of Vitamin E in Healthy Adults with and without Vitamin E Supplementation 252
15.7.4 Estimates of Possible Systemic Vitamin Exposure Using the UHMWPE Articulation Components for Total Joint Arthroplasty 253
15.7.5 Animal Studies to Determine the Local Effects of Vitamin E in the Joint Space 253
15.8 Conclusion and Future Prospects 254
15.9 Acknowledgments 254
References 254
Chapter 16. Vitamin-E-Blended UHMWPE Biomaterials 258
16.1 Introduction 258
16.2 Vitamin E as an Antioxidant for Polyolefins 259
16.3 Vitamin E Blends in Food Packaging 260
16.4 Vitamin E Studies from Japan 261
16.5 Vitasul and Vitamin E Studies from Austria 261
16.6 Vitamin E Studies from Italy 263
16.7 Vitamin E Blends and Thresholds for Oxidative Stability 264
16.8 Vitamin E Blends and Mechanical Behavior 265
16.9 Vitamin E Blends and Crosslinking Efficiency 266
16.10 Summary and Conclusion 266
16.11 Acknowledgments 266
References 267
Chapter 17. Composite UHMWPE Biomaterials and Fibers 270
17.1 Introduction 270
17.2 CFR UHMWPE Composite: Poly II 271
17.3 UHMWPE Homocomposites 273
17.4 UHMWPE Matrix Composites for Orthopedic Bearings 275
17.5 Polyethylene-hydroxyapatite Composites 276
17.6 UHMWPE Fibers 276
17.7 Summary 277
17.8 Acknowledgments 277
References 278
Chapter 18. UHMWPE/Hyaluronan Microcomposite Biomaterials 280
18.1 Introduction 280
18.2 Surface Modification of UHMWPE 281
18.3 Polyurethanes and Hydrogels 281
18.4 Hyaluronan 282
18.5 Synthesis and Processing of UHMWPE/HA Microcomposites 284
18.5.1 UHMWPE/HA 284
18.5.2 Crosslinked UHMWPE/HA 286
18.5.3 Crosslinked Compatibilized UHMWPE/HA 287
18.6 Chemical and Physical Characterization of UHMWPE/HA Biomaterials 287
18.6.1 UHMWPE/HA Composition 287
18.6.2 UHMWPE/HA Hydrophilicity 288
18.6.3 UHMWPE/HA Biostability 289
18.6.4 UHMWPE Crystallinity in UHMWPE/HA 289
18.7 Mechanical and Tribological Characterization of UHMWPE/HA Biomaterials 290
18.7.1 Tensile Properties 290
18.7.2 Wear Resistance 291
18.8 Sterilization of UHMWPE/HA Biomaterials 293
18.9 Biocompatibility of UHMWPE/HA Biomaterials 294
18.10 Commercialization of UHMWPE/HA Biomaterials 294
18.11 Conclusion 294
18.12 Acknowledgments 294
References 295
Chapter 19. High Pressure Crystallized UHMWPEs 298
19.1 Introduction 298
19.2 Extended Chain Crystallization 299
19.2.1 Phase Diagram for PE 301
19.3 Hylamer 302
19.3.1 Structure and Properties 303
19.3.2 In Vitro Studies of Hylamer 303
19.3.3 In Vitro Studies of Hylamer-M 304
19.3.4 Clinical Studies of Hylamer in Hip Arthroplasty 304
19.3.5 Clinical Studies of Hylamer in the Knee 305
19.3.6 Hylamer: A Current Perspective 306
19.4 Crosslinking Followed by High-pressure Crystallization 306
19.5 High-pressure Crystallization Followed by Crosslinking 307
19.6 Summary 307
19.7 Acknowledgments 307
References 307
Chapter 20. Compendium of Highly Crosslinked UHMWPEs 312
20.1 Introduction 312
20.2 ALTRX 313
20.2.1 Development History and Overview 313
20.2.2 Properties and In Vitro Performance 314
20.2.3 Clinical Results 314
20.3 Arcom XL Polyethylene 314
20.3.1 Development History and Overview 315
20.3.2 Properties and In Vitro Performance 315
20.3.3 Clinical Results 315
20.4 Crossfire 315
20.4.1 Development History and Overview 315
20.4.2 Properties and In Vitro Performance 315
20.4.3 Clinical Results 316
20.5 Durasul 316
20.5.1 Development History and Overview 316
20.5.2 Properties and In Vitro Performance 318
20.5.3 Clinical Results 318
20.6 E-poly HXLPE 318
20.6.1 Development History and Overview 319
20.6.2 Properties and In Vitro Performance 319
20.6.3 Clinical Results 319
20.7 Longevity 319
20.7.1 Development History and Overview 319
20.7.2 Properties and In Vitro Performance 321
20.7.3 Clinical Results 321
20.8 Marathon 321
20.8.1 Development History and Overview 322
20.8.2 Properties and In Vitro Performance 323
20.8.3 Clinical Results 323
20.9 Prolong 323
20.9.1 Development History and Overview 324
20.9.2 Properties and In Vitro Performance 324
20.9.3 Clinical Results 325
20.10 X3 325
20.10.1 Development History and Overview 325
20.10.2 Properties and In Vitro Performance 325
20.10.3 Clinical Results 325
20.11 XLK 326
20.11.1 Development History and Overview 326
20.11.2 Properties and In Vitro Performance 326
20.11.3 Clinical Results 326
20.12 XLPE 326
20.12.1 Development History and Overview 327
20.12.2 Properties and In Vitro Performance 327
20.12.3 Clinical Results 327
20.13 The Future for Highly Crosslinked UHMWPE 327
20.14 Acknowledgments 327
References 327
Chapter 21. Mechanisms of Crosslinking, Oxidative Degradation and Stabilization of UHMWPE 330
21.1 Introduction 330
21.2 Mechanisms of Crosslinking 331
21.2.1 Mechanism of Macroradical Formation During Irradiation 331
21.2.2 Reaction of Isolated Radicals 332
21.2.3 Y-Crosslinking Mechanism 332
21.2.4 H-Crosslinking Mechanism 333
21.3 UHMWPE Oxidation 333
21.3.1 Introduction 333
21.3.2 UHMWPE Post-irradiation Oxidation 334
21.4 Critical Products of the Oxidation Process: Macroradicals 335
21.4.1 Alkyl Macroradical (R[sup(& #8226
21.4.2 Peroxy Macroradical (ROO[sup(& #8226
21.4.3 Alkoxy Macroradical (RO[sup(& #8226
21.5 Critical Products of the Oxidation Process: Oxidized Products 335
21.5.1 Hydroperoxide (ROOH) 335
21.5.2 Ketone (R[sub(2)]CO) 335
21.5.3 Carboxylic Acid (RCOOH) 336
21.5.4 Sec-alcohol (R[sub(2)]CHOH) 336
21.5.5 Ester 336
21.6 Considerations on Accelerated Aging Methods: Comparison Between Postirradiation Oxidation and Thermal Oxidation 336
21.6.1 Temperature Effects During Irradiation 337
21.6.2 Distribution of Oxidized Compounds in the New UHMWPE Prosthetic Components 337
21.6.3 Postoxidative Degradation after Implant Manufacture 338
21.7 Stabilization of UHMWPE 339
21.7.1 Introduction 339
21.7.2 Chemical Mechanisms of Vitamin E Stabilization 340
21.7.3 Determination of the Vitamin E Content in UHMWPE 341
21.8. In Vivo Absorption of LIPIDS 341
21.9 Chemical properties of Wear Debris 341
21.10 Acknowledgments 342
References 342
Chapter 22. In Vivo Oxidation of UHMWPE 346
22.1 Introduction 346
22.2 Perspective of In Vivo Oxidation in the 1980s to the Present 347
22.3 Experimental Techniques for Studying In Vivo Oxidation 349
22.3.1 Institutional Procedures and Study Design 349
22.3.2 Experimental Techniques 350
22.3.3 Correlation of In Vivo Oxidation and Mechanical Behavior in Retrievals 352
22.4 Clinical Significance of In Vivo Oxidation 352
22.4.1 In Vivo Oxidation and Total Hip Arthroplasty 352
22.4.2 In Vivo Oxidation and Total Knee Arthroplasty 354
22.5 Laboratory Simulation of In Vivo Oxidation 357
22.6 Summary and Conclusion 359
22.7 Acknowledgments 359
References 360
Chapter 23. Pathophysiologic Reactions to UHMWPE Wear Particles 362
23.1 Introduction 362
23.2 Rationale for Evaluating Tissue Responses 363
23.3 Immune System 363
23.3.1 Adaptive Immune Response 364
23.3.2 Cytokines and Chemokines 364
23.4 Immunologic Responses to Joint Replacement UHMWPE Wear Debris 364
23.5 In Vitro and In Vivo Models Used to Study the Immune Response to UHMWPE Wear Debris 367
23.6 Inflammatory- and Noninflammatory-based Histomorphologic Changes in Periprosthetic Tissues 368
23.7 Current Considerations Based on More Recent Findings and Approaches to Tissue Analysis 369
23.8 Exacerbation of the Immune Response to Wear Debris as a Result of Subclinical Infection 370
23.9 Comparative Pathophysiologic Changes in Periprosthetic Hip Tissues from Historical and Highly Crosslinked UHMWPE Implant Retrievals 370
23.10 Conclusion 371
23.11 Acknowledgments 371
References 371
Chapter 24. Characterization of Physical, Chemical, and Mechanical Properties of UHMWPE 376
24.1 Introduction 376
24.2 What does the FDA Require? 376
24.3 Physical Property Characterization 377
24.3.1 Differential Scanning Calorimetry 377
24.3.2 Scanning Electron Microscopy 379
24.3.3 Intrinsic Viscosity 380
24.3.4 Fusion Assessment 381
24.3.5 Transmission Electron Microscopy 382
24.3.6 Density Measurements 382
24.4 Chemical Property Characterization 382
24.4.1 Trace Element Analysis 382
24.4.2 Fourier Transform Infrared Spectroscopy 383
24.4.3 Electron Spin Resonance 384
24.4.4 Swell Ratio Testing 385
24.5 Mechanical Property Characterization 386
24.5.1 Poisson's Ratio 386
24.5.2 J-Integral Testing 386
24.5.3 Tensile Testing 386
24.5.4 Fatigue Testing 387
24.5.5 Creep 387
24.5.6 Impact Testing 388
24.5.7 Small Punch 388
24.6 Other Testing 388
24.7 Conclusion 388
References 388
Chapter 25. Tribological Assessment of UHMWPE in the Hip 390
25.1 Introduction 390
25.2 Biomechanical Factors 390
25.3 Biological Factors 392
25.4 Biomaterial Factors 393
25.5 Wear Ranking and Magnitude 395
25.6 OBM Developments 395
25.7 Standardization 396
25.8 Summary 396
25.9 Acknowledgment 397
References 397
Chapter 26. Tribological Assessment of UHMWPE in the Knee 402
26.1 Introduction 402
26.2 Pin-on-disc Testing of UHMWPE Destined for Knee Replacements 403
26.3 Testing UHMWPE Within Whole TKR Systems 405
26.3.1 Degrees of Freedom and a Suitable Joint Coordinate System 405
26.3.2 Brief History of Knee Wear Simulators 407
26.3.3 Contemporary Knee Wear Simulators and the Much-Debated Force- versus Displacement-Control Paradigms 409
26.3.4 Force-Control TKR Simulation for UHMWPE Wear Testing 411
26.3.5 Soft Tissue Simulation in the Force-Control Test Method 412
26.3.6 TKR Kinematics Measured from the Force-Control Wear Testing Method 416
26.3.7 Standardization of the Displacement-Control TKR Simulation Method for Wear Testing 418
26.4 Considerations and Pitfalls in Knee Wear Testing of UHMWPE 419
26.4.1 Variable Control and the Number of TKR/UHMWPE Samples to Test 419
26.4.2 Soaking UHMWPE Prior to Testing and Soak Controls during Testing 422
26.4.3 Symmetry of Applied Inputs and Simulator Tuning 423
26.4.4 Choice of Lubricant in Testing UHMWPE Wear in Knee Replacements 425
26.5 Concluding Remarks and Future Directions in UHMWPE and TKR Longevity Test Methods 427
References 427
Chapter 27. Characterization of UHMWPE Wear Particles 430
27.1 Introduction 430
27.2 Rationale for Wear Particle Isolation 430
27.3 Delipidization of Samples 431
27.4 Alkali Digestion of Periprosthetic Tissues and Simulator Lubricants 431
27.5 Acid Digestion of Periprosthetic Tissues and Simulator Lubricants 431
27.6 Enzyme Digestion of Periprosthetic Tissues and Simulator Lubricants 432
27.7 Centrifugation of Samples 432
27.8 Filtering to Recover Particles 432
27.9 Polarized Light Microscopy of Tissue Samples 432
27.10 Scanning Electron Microscopy Analysis 433
27.11 Image Analysis of UHMWPE Wear Particles 433
27.12 Automated Particle Analysis 434
27.13 Standards 434
27.14 Particle Measurements (Size/Shape Descriptors) 435
27.15 Predicting Functional Biological Activity 436
27.15.1 Materials 437
27.15.2 Methods 437
27.15.3 Results 438
27.16 Conclusion 441
References 441
Chapter 28. Clinical Surveillance of UHMWPE Using Radiographic Methods 444
28.1 Introduction 444
28.2 Early Manual Methods for Radiographic Measurement 445
28.3 Radiostereometric Analysis 445
28.4 Non-RSA methods 447
28.4.1 Hip Analysis Suite 447
28.4.2 PolyWare 449
28.5 Other Factors to Consider 450
References 451
Chapter 29. ESR Insights into Macroradicals in UHMWPEM 454
29.1 Introduction 454
29.2 Basic Principle of ESR 455
29.3 Free Radicals in UHMWPE 457
29.3.1 Alkyl Radical 457
29.3.2 Allyl Radical 457
29.3.3 Polyenyl Radical 458
29.3.4 Peroxy Radical 458
29.3.5 ESR Evidence of the Peroxy Radical in UHMWPE 460
29.3.6 Half-Life of the Peroxy Radical in UHMWPE 461
29.4 Long-lived Oxygen-induced Radical in UHMWPE 461
29.4.1 ESR Evidence of the Long-Lived Radicals in UHMWPE 461
29.4.2 Growth and Decay of the Oxygen-induced Radicals 463
29.4.3 Identification of the Oxygen-induced Radicals by ESR 463
29.5 Intermediate Radicals 466
29.6 ESR of Vitamin E-doped UHMWPE 467
29.7 Quantitative ESR in UHMWPE 469
References 470
Chapter 30. Fatigue and Fracture of UHMWPE 472
30.1 Introduction 472
30.2 Fatigue Resistance 473
30.2.1 Basic Concepts of Fatigue Resistance 473
30.2.2 Fatigue Analysis: Total Life Approach 473
30.2.3 Total Life Fatigue Testing in UHMWPE 474
30.2.4 Fatigue Analysis: Defect Tolerant Approach 474
30.2.5 Fatigue Crack Propagation Testing in UHMWPE 476
30.2.6 Viscoelastic Fatigue Crack Propagation 476
30.2.7 Non-Conventional Fatigue Experimental Approaches 480
30.3 Fracture resistance 481
30.3.1 Introduction 481
30.3.2 Uniaxial Tensile Failure: Work to Fracture and Estimated K[sub(C)] 481
30.3.3 Izod and Charpy Impact Tests 481
30.3.4 Elastic–Plastic Fracture Mechanics and the J-integral Concept 482
30.3.5 J-integral Based Fracture Toughness Testing 484
30.3.6 J-integral Fracture Toughness of UHMWPE 488
30.4 Summary and Conclusion 490
References 490
Chapter 31. Development and Application of the Notched Tensile Test to UHMWPE 494
31.1 Introduction 494
31.2 Overview of Notch Behavior 494
31.3 Overview of the Notched Tensile test method 497
31.3.1 Specimen Geometry and Loading 497
31.3.2 Data Acquisition and Stress–Strain Determination 497
31.3.3 Mechanical Characterization of Notch Effects 497
31.3.4 Material Characterization and Fracture Micromechanism 498
31.4 Recent Studies of Conventional and Highly Crosslinked UHMWPE Materials 499
31.4.1 Mechanical Characterization of Notch Effects 499
31.4.2 Material Characterization and Fracture Micromechanism 499
31.4.3 Hybrid Model Finite Element Analysis 500
31.5 The Effects of Notches on Deformation and Fracture Mechanisms 502
31.6 Conclusion and Future Directions 503
Acknowledgements 503
References 504
Chapter 32. Development and Application of the Small Punch Test to UHMWPE 506
32.1 Introduction 506
32.2 Overview and Metrics of the Small Punch Test 507
32.3 Accelerated and Natural Aging of UHMWPE 508
32.3.1 In Vivo Changes in Mechanical Behavior of UHMWPE 510
32.4 Effect of Crosslinking on Mechanical Behavior and Wear 511
32.5 Shear Punch Testing of UHMWPE 513
32.6 Fatigue punch testing of UHMWPE 514
32.7 Conclusion 515
References 517
Chapter 33. Nano- and Microindentation Testing of UHMWPE 518
33.1 Introduction 518
33.2 Depth-sensing Indentation Testing Methods 519
33.3 Indentation Tests on UHMWPE: Structure-property Testing 522
33.3.1 DSI Testing: Effects of Processing, Surface Preparation, and Prior Deformation 522
33.3.2 DSI Testing: Effects of Oxidation and Crosslinking 524
33.3.3 DSI Testing: Viscoelastic Behavior 526
33.4 Nanoscratch Single Asperity Wear Tests and their Effects on Indentation Behavior 527
33.5 Summary and Conclusion 529
33.6 Acknowledgments 529
References 529
Chapter 34. MicroCT Analysis of Wear and Damage in UHMWPE 532
34.1 Introduction 532
34.2 MicroCT Scanning 533
34.2.1 Practical Considerations in Scanning 533
34.2.2 Motion Artifacts During Scanning 533
34.2.3 Image Segmentation 533
34.3 Evaluation of Penetration in THA Using Geometric Primitives 533
34.3.1 Three-Dimensional Alignment 534
34.3.2 Volume Measurement 534
34.3.3 Uncertainty Analysis 535
34.4 Evaluation of Penetration in nonregularly Shaped Components 535
34.4.1 Volumetric Penetration in Total Elbow Replacement 536
34.4.2 Spatial Visualization of Penetration in Total Elbow Replacement Using Manual Registration 536
34.4.3 Quantitative, Spatial Visualization of Penetration in Total Disc Replacements Using Automated Registration 537
34.5 Assessing Subsurface Cracking Using MicroCT 538
34.6 Using MicroCT to Visualize Third-Body Wear 538
34.7 Conclusion 539
34.8 Acknowledgments 539
References 539
Chapter 35. Computer Modeling and Simulation of UHMWPE 540
35.1 Introduction 540
35.2 Overview of Available modeling and Simulation Approaches 541
35.3 Characteristic Material Behavior of UHMWPE 542
35.4 Material models for UHMWPE 544
35.4.1 Linear Elasticity 545
35.4.2 Hyperelasticity 545
35.4.3 Linear Viscoelasticity 546
35.4.4. Isotropic J[sub(2)]-Plasticity 547
35.4.5 The Hybrid Model 548
35.5 Discussion 551
35.6 Acknowledgments 552
References 552
Index 554
A 554
B 554
C 554
D 555
E 556
F 556
G 557
H 557
I 557
J 558
K 558
L 558
M 559
N 559
O 559
P 560
Q 561
R 561
S 561
T 562
U 563
V 563
W 563
X 563
Y 564
Z 564