Saturday, August 30. 2008
Nanotechnology may allow hip implants to sense growth of
new boneLink
http://www.foresight.org/nanodot/?p=2788
Growing multiwalled carbon nanotubes on a titanium
surface enhances the electrochemical behavior of the
surface in a way that might lead to better implants
for hip replacements. The nanotech-prepared titanium
surface serves as a sensor to detect bone formation.
As reported by James Tyrrell at nanotechweb.org
(requires free registration) "Nanotubes
on the look out for new bone".
Multiwalled carbon nanotubes (MWCNTs) grown
in pores on a titanium (Ti) surface are ideal
for detecting bone growth, according to Thomas
Webster and his team at Brown University, US [Nanotechnology
abstract]. By adding the biosensing
structure to the surface of orthopedic implants,
the inventors hope to monitor the success of
procedures such as hip replacements in situ.
Poor adhesion to the surrounding bone is the
most common cause of hip replacement failure.
Currently, the diagnosis of new bone growth can
be problematic as today’s imaging techniques
each have their own limitations and difficulties
— something that Webster and his colleagues hope
to overcome.
"The idea is that our sensor will communicate
the status of the surrounding tissue via radio
frequencies to a handheld device," Webster told nanotechweb.org.
"In fact, we’ve taken things a step further and
coated our sensor with a drug-containing polymer
layer that can be degraded to release bone
building agents on demand."
…Next, the team plans to begin animal
studies. "It’s a big and important jump to
determine if the sensors will work in an
animal," said Webster. "We’ll be using rats and
analyzing whether new bone growth can be
measured and then controlled."
Friday, August 29. 2008
Link:
Click here to view complete article
Distribution of Chromium and Cobalt Ions in Various Blood Fractions After
Resurfacing Hip Arthroplasty
Leonard R. Walter MBBS(Syd), FRACS,
FAOrthA, Ed Marel MBBS(Syd), FRCS Ed (Orth),
FRACS, FAOrthAa,
Richard Harbury MBBS(Syd), FRACS, FAOrthAa
and Jenny Wearne RN
aPeninsula Orthopaedics Research
Institute, DEE WHY NSW 2099, Australia
Received 28 November 2006;
accepted 7 July 2007
Abstract
The most appropriate blood fraction for the
measurement of metal ions in patients with
metal-on-metal implants is controversial. We
compared chromium (Cr) and cobalt (Co) ion
levels in 29 patients after unilateral hip
resurfacing with a size 54-mm femoral Birmingham
Hip Resurfacing Prosthesis (Smith and Nephew,
London, UK). All had well-functioning
arthroplasties between 5 and 59 months after
implantation. Ion levels were measured in serum, plasma, red cells, and whole
blood in each patient. Our results indicate that only very minor amounts of Cr
and Co are associated with red blood cells, with most being associated with
serum/plasma. Previous studies using corrosion to produce the ion load have
showed a predominance of Cr in the red blood cells. They have also shown that
the cellular uptake of Cr is an indicator of its valence. This difference in
distribution with our results is indirect evidence that the Cr released from
wear of this implant is probably in the more benign trivalent form. It also
suggests that most of the metal loss from a normally wearing bearing may be from
wear rather than corrosion. If blood is to be used to assess rates of wear and
systemic ion levels, then serum gives a better reflection of the true levels
than red blood cells.
Friday, August 8. 2008
Link -
Click here to see full article
Aug. 8, 2008
Since its introduction a decade ago, metal-on-metal hip resurfacing has
become increasingly popular because it may conserve femoral bone, increase
functional ability and be easier to revise than other procedures, according to
an article published in the August issue of the Journal of Bone & Joint Surgery.
Michael A. Mont, M.D., of Sinai Hospital of Baltimore, and a colleague reviewed
clinical results - primarily from studies conducted in England, Australia and
Western Europe -- and highlighted 10 important lessons learned during the past
10 years.
The researchers found that metal-on-metal hip resurfacing now accounts for about
10 percent of total hip arthroplasties. Among the lessons they highlight is that
patient selection is the key to success. They cite Australian data on more than
10,000 patients showing that metal-on-metal hip resurfacing is associated with
similar or improved survivorship compared to standard total hip arthroplasty in
men under age 65 but not in men over age 65, and that metal-on-metal hip
resurfacing is associated with a higher risk of short-term failure in men over
age 65 and in all women.
"In the Australian registry, hips that underwent resurfacing as treatment for
osteoarthritis have had better survival than those that underwent resurfacing
for the treatment of developmental dysplasia, inflammatory arthritis and
osteonecrosis," the authors write. "In summary, resurfacing hip arthroplasty has
had a tremendous increase in popularity because of the potential benefits of
femoral bone conservation, possible increased functional ability, and ease of
potential revision procedures. In young men, the survivorship has been similar
to that of standard total hip arthroplasty."
Although none of the authors received outside funding or grants in support of
their research, one or more of them reported that they or their family members
received grants or payments from Wright Medical and DePuy during the past year.
Monday, August 4. 2008
Link
http://www.govhealthit.com/online/news/350502-1.html
By Peter Buxbaum
Published on August 4, 2008
The Food and Drug Administration has proposed a
program that would query public and private databases to help study the efficacy
of orthopedic implants.
FDA will issue a request for quotations next month in an effort to identify
companies that could evaluate orthopedic implant registries for participation in
the program.
The program is part of the broader Sentinel Initiative FDA launched earlier this
year. The broader effort is intended to monitor and provide early warnings of
potential problems with FDA-approved medical products.
The implant program would “create a national network of registries for the FDA
in support of the Sentinel Initiative,” according to an FDA announcement posted
July 25. Implants of interest would include total hip, total knee, hip
resurfacing, intervertebral disc implants and ankle devices.
The program would create a distributed network to enable FDA to query multiple
data sources for information about medical products. As envisioned, queries to
the network would be accomplished with minimal data transfer and would protect
patient privacy.
FDA’s current post-market surveillance programs require “health care
professionals and patients to first recognize an association between an adverse
effect and a medical product, and then report it to FDA,” an FDA spokesperson
said. “Most adverse events are never reported, and when they are, the
information provided is incomplete.”
FDA officials envision being able to search government databases, such as the
Medicare database, private and public medical claims databases, and electronic
health record systems, the spokesperson said.
The proposed evaluations of the orthopedic implant registries will lead to
recommendations for involvement of the most promising data sources, the FDA
announcement states.
The Sentinel Initiative “could also ultimately facilitate data mining and other
research-related activities,” the spokesperson added.
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