UHMWPE Biomaterials Handbook, Third Edition: Ultra High Molecular Weight Polyethylene in Total Joint Replacement and Medical Devices

823 Pages·2016·119.19 MB·English

by  Steven M. Kurtz Ph.D

UHMWPE
BIOMATERIALS
HANDBOOK
Ultra-High Molecular Weight
Polyethylene in Total Joint
Replacement and Medical Devices
Third Edition
Edited by
Steven M. Kurtz, PhD
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To Karen, for listening to all my stories; and to Katie, Peter, Michael,
Sophia, and Andrew, for fatherhood.
List of Contributors
Mazen Al-Hajjar, PhD Avram A. Edidin, PhD
Institute of Medical and Biological Engineering, School of Biomedical Engineering, Science and
School of Mechanical Engineering, University of Health Systems, Drexel University, Philadelphia,
Leeds, Leeds, UK PA, USA
Murat Ali, PhD Jevan Furmanski, PhD
Institute of Medical and Biological Engineering, ExxonMobil Corporate Strategic Research,
School of Mechanical Engineering, University of Annandale, NJ, USA
Leeds, Leeds, UK
Stefan M. Gabriel, PhD, PE
Doruk Baykal, PhD Moximed, Hayward, CA, USA
Exponent, Inc., Philadelphia, PA, USA
Jeremy L. Gilbert, PhD
Anuj Bellare, PhD Department of Biomedical and Chemical
Orthopaedic Nanotechnology Laboratory, Brigham Engineering, L.C. Smith College of Engineering and
and Women’s Hospital, Boston, MA, USA Computer Science, Syracuse University, Syracuse,
NY, USA
Jorgen Bergström, PhD
Veryst Engineering, Needham, MA, USA
Hani Haider, PhD
Department of Orthopaedic Surgery and
Karlien Boon-Ceelen, PhD
Rehabilitation, Orthopaedics Biomechanics and
DSM Biomedical, Sittard, Netherlands
Advanced Surgical Technologies Laboratory,
University of Nebraska Medical Center, Omaha,
Anton E. Bowden, PhD, PE
NE; Biomedical Engineering Practice, Exponent,
Department of Mechanical Engineering, Brigham
Inc., Philadelphia, PA, USA
Young University, Provo, UT, USA
Allyson Ianuzzi, PhD
Pierangiola Bracco, PhD
DePuy Synthes, West Chester, PA, USA
Chemistry Department and Nanostructured
Interfaces and Surfaces (NIS) Centre, University of
Kazuhiko Ishihara, PhD
Torino, Torino, Italy
Department of Materials Engineering, School of
Engineering, The University of Tokyo, Bunkyo-ku,
Charles R. Bragdon, PhD
Tokyo, Japan
Harris Orthopedic Laboratory, Massachusetts
General Hospital; Department of Orthopaedic
Muhammad Shah Jahan, PhD
Surgery, Harvard Medical School, Boston, MA, USA
Department of Physics, The University of Memphis,
Memphis, TN, USA
Gavin Braithwaite, PhD
Cambridge Polymer Group, Boston, MA, USA
Susan P. James, PhD
Luigi Costa, PhD Department of Mechanical Engineering, School of
Chemistry Department and Nanostructured Biomedical Engineering, Colorado State University,
Interfaces and Surfaces (NIS) Centre, University of Fort Collins, CO, USA
Torino, Torino, Italy
Louise M. Jennings, PhD
Judd S. Day, PhD Institute of Medical and Biological Engineering,
Exponent, Inc., Drexel University, Philadelphia, School of Mechanical Engineering, University of
PA, USA Leeds, Leeds, UK
xix
xx List of Contributors
Adam Kozak, BS Kevin Ong, PhD
Cambridge Polymer Group, Boston, MA, USA Exponent, Inc., Philadelphia, PA, USA
Steven M. Kurtz, PhD Ebru Oral, PhD
Exponent, Inc.; Drexel University, Philadelphia, Harris Orthopedic Laboratory, Massachusetts
PA, USA General Hospital; Department of Orthopaedic
Surgery, Harvard Medical School, Boston, MA,
Masayuki Kyomoto, PhD USA
Department of Materials Engineering, School
of Engineering; Division of Science for Joint Jasmine D. Patel, PhD
Reconstruction, Graduate School of Medicine, Exponent, Inc., Philadelphia, PA, USA
The University of Tokyo, Bunkyo-ku, Tokyo,
Japan; Research Department, KYOCERA Medical Maria Persson, PhD
Corporation, Yodogawa-ku, Osaka, Japan DSM Biomedical, Sittard, Netherlands
Daniel MacDonald, MS José Antonio Puértolas, PhD
School of Biomedical Engineering, Science and Instituto de Investigación en Ingeniería de Aragón,
Health Systems, Drexel University, Philadelphia, I3A, Universidad de Zaragoza, Zaragoza, Spain
PA, USA
Clare M. Rimnac, PhD
Michael T. Manley, FRSA, PhD Department of Mechanical and Aerospace
Stryker Orthopaedics, Mahwah, NJ, USA; Engineering, Case Western Reserve University,
Department of Biomechanics, University of Bath, Cleveland, OH, USA
Bath, UK
Herb Schwartz, PhD
Francisco J. Medel, PhD BioPoly LLC, Schwartz Biomedical LLC, Fort
Department of Mechanical Engineering, School Wayne, IN, USA
of Engineering and Architecture, ICMA (Institute
of Materials Science of Aragón), University of Ryan Siskey, MS
Zaragoza, Zaragoza, Spain Exponent, Inc., Philadelphia, PA, USA
Chimba Mkandawire, PhD, CAISS Harold Smelt, MS
Exponent, Inc., Atlanta, GA, USA DSM Biomedical, Sittard, Netherlands
Toru Moro, MD, PhD Michael C. Sobieraj, MD, PhD
Division of Science for Joint Reconstruction, Department of Orthopaedic Surgery, New York
Graduate School of Medicine; Sensory & Motor University Hospital for Joint Diseases, New York,
System Medicine, Faculty of Medicine, The NY, USA
University of Tokyo, Bunkyo-ku, Tokyo, Japan
Stephen Spiegelberg, PhD
Orhun K. Muratoglu, PhD Cambridge Polymer Group, Boston, MA, USA
Harris Orthopedic Laboratory, Massachusetts
General Hospital; Department of Orthopaedic Marla J. Steinbeck, MT(ASCP), PhD
Surgery, Harvard Medical School, Boston, MA, USA School of Biomedical Engineering and Health
Sciences; Department of Orthopaedic Surgery,
Venkat Narayan, PhD Drexel University College of Medicine,
DePuy Synthes Joint Reconstruction, Warsaw, IN, Philadelphia, PA, USA
USA
Ashley A. Stratton-Powell, BSc (Hons), MSc
Rachael (Kurkowski) Oldinski, PhD Institute of Medical and Biological Engineering,
School of Engineering, University of Vermont, School of Mechanical Engineering, University of
Burlington, VT, USA Leeds, Leeds, UK
List of Contributors xxi
Joanne L. Tipper, BSc (Hons), PhD James D. Wernle, PhD
Institute of Medical and Biological Engineering, Department of Biomedical and Chemical
School of Mechanical Engineering, University of Engineering, L.C. Smith College of Engineering and
Leeds, Leeds, UK Computer Science, Syracuse University, Syracuse,
NY, USA
Sai Y. Veruva, PhD Candidate
School of Biomedical Engineering and Health Matthew Zagorski, MS, CPP
Sciences, Drexel University, Philadelphia, DePuy Synthes – Technical Center, West Chester,
PA, USA PA, USA
Marta L. Villarraga, PhD Min Zhang, PhD
Exponent, Inc.; Drexel University, Philadelphia, Department of Bioengineering, University of
PA, USA Washington, Seattle, WA, USA
Foreword
“It was the best of times, it was the worst of as disappointing outcomes of certain metal-on-metal
times, it was the age of wisdom, it was the age hip technologies. Despite these challenges, the field
of foolishness, it was the epoch of belief, it was of UHMWPE biomaterials, with its successful clini-
the epoch of incredulity …” cal track record, is well positioned to flourish over
the long term in a value-based health-care economy.
–Charles Dickens, A Tale of Two Cities The third edition of the Handbook continues the
tradition of the second edition with the involvement
I am increasingly reminded of how appropriate of many UHMWPE experts to provide an expanded
these words of Dickens reflect the current state of ul- and diverse perspective on advancements in a broad
tra-high molecular weight polyethylene (UHMWPE) range of selected topics. For example, in this edition,
in orthopedics! From the perspective of biomateri- I have asked pioneers in the innovation of new anti-
als science and worldwide acceptance, UHMWPE is oxidants and MPC-grafted materials to explain the
now experiencing the best of times. The successful development history and findings for their respec-
clinical history of UHMWPE biomaterials continues tive family of cross-linked polyethylenes. Nearly all
to expand at a surprising pace. When the first edition the chapters have undergone revision and updated
of the Handbook was published in 2004, radiation to reflect advancements over the past 6 years since
cross-linked materials had been recently introduced. the second edition was published. A second major
In 2009, when the second edition was published, a change for the current volume is its breadth: the first
second generation of radiation cross-linked materi- edition contained 15 chapters, the second edition in-
als had been recently introduced for clinical use. To- cluded 35, and the third edition now includes 41. The
day, vitamin-E stabilized UHMWPE is established major expansion of the current edition not only re-
as an internationally standardized biomaterial, and flects the feedback I received from readers in both in-
an alternative antioxidant has been clinically intro- dustry and academia but also better captures my per-
duced as well. In retrospect, the continued speed of sonal wishes for a more comprehensive treatment of
advancement in this field is astonishing, considering the subject that simply wasn’t practical with the first
that for the first three decades of the clinical history edition. For example, although I wanted to include
of UHMWPE biomaterials (1962–1997), few clini- a standalone chapter on first-generation HXLPEs 6
cally relevant innovations occurred beyond the re- years ago in the second edition, I felt that consensus
moval of calcium stearate and changes in steriliza- in the field and my own research on the topic had not
tion practice. Because of the continually expanding yet advanced to the point where a dedicated chapter
role of UHMWPE in the field or orthopedics, I felt was appropriate. As a result, this third edition of the
that it was appropriate to undertake a major revision Handbook continues to capture, to an even greater
of the second edition, culminating in the preparation extent than its predecessor, the incredible breadth
of this current volume. and depth of scientific inquiry in the field of UHM-
From the perspective of orthopedics, this is a very WPE biomaterials. I am indebted to my collaborators
challenging time to deliver cost-effective care in the for dedicating their personal time and expertise to as-
face of what will surely be increasing global demand sist me in this undertaking.
for total joint arthroplasty in the future. This third The first edition of the Handbook has its origins
edition arrives at a time of many historical changes in a review article, “Advances in the sterilization,
in the manufacture and distribution of orthopedic im- processing, and cross-linking of ultra-high molecu-
plants, which is currently in a period of change and lar weight polyethylene for total joint arthroplasty”
consolidation. Orthopedics is also adjusting to con- (Biomaterials 1999; 20: 1659–1688), which I coau-
troversy in the field of alternative bearing materials, thored with Orhun Muratoglu, Mark Evans, and Av
with the decline in usage of metal-on-metal bearings. Edidin. Our review was written between 1997 and
There can be no doubt that orthopedics has entered 1998, at a time when highly cross-linked and ther-
a new phase of conservativism, both in reaction to mally treated UHMWPE materials were about to
the growing economic pressures in medicine as well be clinically introduced for total hip replacement.
xxiii
xxiv Foreword
Several other important milestones in the clinical mind, I have also taken some care to review the his-
use of UHMWPE had occurred, including the aban- torical development of UHMWPE bearings for joint
donment of gamma sterilization in air (at least in the replacement.
United States), and the trend to reduce calcium stea- The story of UHMWPE in orthopedics still con-
rate (a processing additive) in the UHMWPE powder. tinues to evolve. Early in 2002, I undertook the task
With the controversy now surrounding metal-on- of expanding my website, the UHMWPE Lexicon
metal hip replacements, the number of bearing mate- (www.uhmwpe.org), with an online monograph of
rial choices available to the orthopedic surgeon has six introductory chapters covering the basic scientific
been effectively simplified than what it was in 2009 principles and clinical performance of UHMWPE in
when the second edition of the Handbook was pub- hip replacement. The response to these online chap-
lished. Yet, even with the advanced technologies and ters was overwhelmingly positive, and encouraged
design options that are available today, we should be me to revise the first six chapters for hardcopy pub-
mindful that for very elderly patients, artificial joints lication, and to develop the additional nine chapters
incorporating conventional UHMWPE will continue for first edition of the UHMWPE Handbook. This
to afford long-term clinical benefits that could poten- website continues today as a repository of UHM-
tially last the rest of these patients’ natural lives. On WPE knowledge as it accumulates in “real time.”
the other hand, modern HXLPEs should provide the Despite my diligent efforts to summarize the state
greatest benefit to young patients (less than 60 years of the art in this field, I appreciate that current trends
in age) who lead an active lifestyle and who need a related to UHMWPE in orthopedics will give way
total hip replacement. For patients in need of knee to new ideas as further clinical data becomes avail-
arthroplasty, shoulder arthroplasty, or total disc re- able in the future. For this reason, I hope that the
placement, conventional UHMWPE continues to UHMWPE Lexicon website (www.uhmwpe.org)
prevail as the polymeric bearing material of choice, will continue to disseminate new research findings
although HXLPE has made recent inroads into the to the orthopedic and polymer research communi-
field of total knee arthroplasty. ties. The Lexicon website and this current Handbook
The latest generation of antioxidant technolo- play complementary roles. When the accumulation
gies has contributed to some confusion among sur- of new ideas and findings has diffused sufficiently
geons and researchers alike regarding the technical into the orthopedic clinical and research practice, it
details associated with second-generation highly will be time once again to update this written work. I
cross-linked UHMWPE. I am also frequently asked look forward to your comments and suggestions for
about the differences between blending and diffus- future expansion of the UHMWPE Lexicon website
ing UHMWPE with vitamin E. My goal in writing and this UHMWPE Handbook.
the UHMWPE Handbook is to explain the common The present edition would not have been possible
concepts underlying all UHMWPE biomaterials, without the suggestions and advice of many support-
as well as the technical differences in specific for- ive colleagues. I am especially grateful to my coau-
mulations for an audience of surgeons, researchers, thors, experts in the fields of joint arthroplasty, spine,
and students who may be starting work in this field. as well as in the testing and evaluation of UHMWPE,
Some of the early chapters in this book may also be who have cheerfully contributed chapters to this
of interest to current or prospective patients who are book on relatively short notice. I have also included
motivated to learn more about current treatment op- acknowledgments at the end of chapters to thank my
tions. Because all of today’s alternative bearing so- many friends and associates for their contributions.
lutions (both highly cross-linked UHMWPE as well
as ceramic bearings) have their origins in the 1950s, —Steven M. Kurtz, PhD
1960s, and 1970s, it is important to understand the Philadelphia, PA
historical context in which first- and second-genera- March 7, 2015
tion HXLPEs were originally developed. With this in [email protected]
1 A Primer on UHMWPE
Steven M. Kurtz, PhD
Exponent, Inc.; Drexel University, Philadelphia, PA, USA
1.1 Introduction chemical changes that arise in UHMWPE due to radia-
tion, sterilization, and processing.
Ultra-high molecular weight polyethylene The purpose of this Handbook is to explore the
(UHMWPE) is a unique polymer with outstanding complexities inherent in UHMWPE and an increas-
physical and mechanical properties. Most notable are ingly diverse field of UHMWPE biomaterials that
its chemical inertness, lubricity, impact resistance, include radiation cross-linking, composites, and anti-
and abrasion resistance. These characteristics of oxidants such as Vitamin E. This book is intended to
UHMWPE have been exploited since the 1950s in a provide the reader with a background in the terminol-
wide range of industrial applications (Figure 1.1), in- ogy, history, and recent advances related to its use in
cluding pickers for textile machinery, lining for coal orthopedics. A monograph such as this is helpful in
chutes and dump trucks, runners for bottling produc- several respects. First, it is important that members
tion lines, as well as bumpers and siding for ships and of the surgical community have access to up-to-date
harbors. Over 90% of the UHMWPE produced in the knowledge about the properties of UHMWPE so that
world is used by industries. this information can be more accurately communi-
For the past 50 years, UHMWPE has also been cated to their patients. Second, members of the ortho-
used in orthopedics as a bearing material in artificial pedic research community need access to timely syn-
joints. Each year, about three million joint replace- thesis of the existing literature so that future studies
ment procedures are performed around the world, are more effectively planned to fill in existing gaps
and the majority of these joint replacements incor- in our current understanding. Finally, this handbook
porate UHMWPE. Despite the success of these re- may also serve as a resource for university students at
storative procedures, orthopedic and spine implants both the undergraduate and graduate levels.
have only a finite lifetime. Wear and damage of the This introductory chapter starts with the basics, as-
UHMWPE components has historically been one of suming the reader is not familiar with polymers, let
the factors limiting implant longevity. In the past alone polyethylene. The chapter provides basic infor-
15 years, highly cross-linked UHMWPE biomateri- mation about polymers in general, describes the struc-
als have shown dramatic reductions in wear and im- ture and composition of polyethylene, and explains
proved long-term survivorship in total hip replace- how UHMWPE differs from other polymers (includ-
ments around the world. The orthopedic community ing HDPE) and from other materials (e.g., metals and
awaits confirmation that these reductions in wear will ceramics). The concepts of crystallinity and thermal
be associated with improved long-term survival in to- transitions are introduced at a basic level. Readers fa-
tal knee replacements as well. miliar with these basic polymer concepts may want to
UHMWPE comes from a family of polymers with a consider skipping ahead to the next chapter.
deceptively simple chemical composition, consisting of
only hydrogen and carbon. However, the simplicity in-
herent its chemical composition belies a more complex 1.2 What is a Polymer?
hierarchy of organizational structures at the molecular
and supermolecular length scales. At a molecular level, The ultra-high molecular weight polyethylene
the carbon backbone of polyethylene can twist, rotate, (UHMWPE) used in orthopedic applications is a type
and fold into ordered crystalline regions. At a supermo- of polymer generally classified as a linear homopoly-
lecular level, the UHMWPE consists of powder (also mer. Our first task is to explain what is meant by all
known as resin or flake) that must be consolidated at of these terms. Before proceeding to a definition of
elevated temperatures and pressures to form a bulk ma- UHMWPE, one needs to first understand what con-
terial. Further layers of complexity are introduced by stitutes a linear homopolymer.
UHMWPE Biomaterials Handbook
1
Copyright © 2016 Elsevier Inc. All rights reserved.
2 UHMWPE Biomaterials Handbook
Figure 1.3 Schematics of linear and branched poly-
mer structures.
Keep in mind that the conceptual models of poly-
mer structure illustrated in Figures 1.2 and 1.3 have
been highly simplified. For example, it is possible for
a copolymer to have a wide range of substructural
elements giving rise to an impressive range of possi-
bilities. In industrial practice, polyethylenes, including
UHMWPE, are frequently copolymerized with other
monomers (e.g., polypropylene) to achieve improved
processing characteristics or to alter the physical and
mechanical properties of the polymer. For example,
according to ISO 11542, which is the industrial stan-
dard for UHMWPE, the polymer can contain a large
concentration of copolymer (up to 50%) and still be re-
ferred to as “UHMWPE.” However, most of the UHM-
WPEs used to fabricate orthopedic implants are homo-
polymers, and so we will restrict our further discussion
to polymers with only a single type of monomer.
The principal feature of a polymer that distin-
guishes it from other materials, such as metals and
ceramics, is its molecular size. In a metallic alloy
Figure 1.1 Dump truck liner of UHMWPE, an exam- or ceramic, the elemental building blocks are indi-
ple of an industrial application for the polymer. vidual metal atoms (e.g., Co, Cr, Mo) or relatively
small molecules (e.g., metal carbides or oxides). In
a polymer, however, the molecular size can comprise
over a hundred thousand monomer units, with molec-
ular weights of up to millions of gram per molecule.
The molecular chain architecture of a polymer also
imparts many unique attributes, including temperature-
and rate-dependence. Some of these unique properties
are further illustrated in the specific case of UHMWPE
Figure 1.2 Schematics of homopolymer and copoly-
in subsequent sections of this chapter. For further back-
mer structure.
ground on general polymer concepts, the reader is re-
ferred to texts by Rodriguez [1] and Young [2].
A polymer is a molecule consisting of many (poly-)
parts (-mer) linked together by chemical covalent
bonds. The individual parts, or monomer segments, 1.3 What is Polyethylene?
of a polymer can all be the same. In such a case, we
have a homopolymer as illustrated in Figure 1.2. If Polyethylene is a polymer formed from ethylene
the parts of a polymer are different, it is termed a (C H ), which is a gas having a molecular weight of
2 4
copolymer. These differences in chemical structure 28. The generic chemical formula for polyethylene is
are also illustrated in Figure 1.2, with generic sym- –(C H ) –, where n is the degree of polymerization.
2 4 n
bols (A, B) for the monomers. A schematic of the chemical structures for ethylene
Polymers can be either linear or branched as illus- and polyethylene are shown in Figure 1.4.
trated in Figure 1.3. The tendency for a polymer to ex- For an ultra-high molecular weight polyethyl-
hibit branching is governed by its synthesis conditions. ene, the molecular chain can consist of as many