Biomedical Engineering Reference
In-Depth Information
7
New ceramics and composites for joint replacement
surgery
M . N . R A H AMA N , Missouri University of Science
and Technology, USA and B . S O N N Y B A L ,
University of Missouri±Columbia, USA
Abstract: Ceramics have been used as an alternative to metal-on-
polyethylene in joint replacement surgery of arthritic hips and knees since
the 1970s. In prosthetic hip and knee bearings, ceramics offer a major
benefit of drastically reduced wear rates and excellent long-term
biocompatibility, which can increase the longevity of prosthetic hip and knee
joints. This benefit is important clinically because hip and knee replacements
have become very common surgical procedures, particularly in the United
States and Europe, and because these procedures are increasingly performed
in younger patients who place greater demands on the prosthetic bearings.
Modern ceramic bearings are safe and reliable if used with components of
proven design and durability. However, catastrophic bearing failure in vivo,
while rare, and the risk of `squeaking' (audible noise) of ceramic bearings,
while low, have served to diminish the enthusiasm of many patients and
orthopedic surgeons for ceramic bearings in total joint replacement. Future
material improvements are actively being investigated to reduce the risk of
ceramic bearing failures even further, and to extend the range of ceramic
bearing components available for total joint replacement. In this chapter, the
properties, applications, and limitations of ceramics that have been used in
orthopedic bearings are reviewed, and the new ceramics and composites that
will be available for joint replacement surgery in the near future are
discussed.
Key words: total joint replacement, orthopedic implants, ceramics, ceramic
matrix composites.
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7.1
Introduction
Arthroplasty devices for replacing the hip joint have been under development
since the early 1900s, but the basic design for modern total hip arthroplasty
(THA) devices is credited to Sir John Charnley who, in the early 1960s, intro-
duced a metal femoral head prosthesis articulating in an ultra-high molecular
weight polyethylene (UHMWPE) acetabular component (Charnley, 1961). THA
and total knee arthroplasty (TKA) are common operations today, particularly in
the US and Europe. More than 500 000 total hip and knee joint replacements are
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