Long-term risks of joint implants
Metals from implants can accumulate in bone tissue

Date:
August 11, 2020
Source:
Charite' - Universita"tsmedizin Berlin
Summary:
Using highly complex analytical techniques, a group of researchers
were able to observe in detail how different metals are released
from joint implants and accumulate in the surrounding bone
tissue. Findings showed a steady release of metals from various
implant components. In contrast to previous assumptions, this was
not related to the degree of mechanical stress involved.



FULL STORY ========================================================================== Using highly complex analytical techniques, a group of researchers from Charite' -- Universita"tsmedizin Berlin were able to observe in detail
how different metals are released from joint implants and accumulate in
the surrounding bone tissue. Findings showed a steady release of metals
from various implant components. In contrast to previous assumptions,
this was not related to the degree of mechanical stress involved. The researchers' findings, which have been published in Advanced Science, will
help to optimize the materials used in implants and enhance their safety.


========================================================================== Modern joint implants restore pain-free mobility of patients with chronic degenerative joint disease, thereby drastically enhancing their quality of life. To ensure long-term mechanical stability, artificial joints are made
from materials containing a range of different metal alloys. A crucial
factor in determining an implant's long-term effectiveness, however,
is its integration into the surrounding bone tissue. Previous studies on implant stability show that friction between the articulating surfaces
(bearing surfaces) can result in the formation of metal debris. This wear debris can lead to osteolysis - - the destruction of bone around the
implant -- which can result in premature loosening of the implant. The possibility of a steady release of metal from other parts of the
prosthesis had not previously received much attention.

A group of researchers led by Dr. Sven Geissler of Charite''s Julius Wolff Institute for Biomechanics and Musculoskeletal Regeneration and BIH Center
for Regenerative Therapies has now studied the spatial distribution and
local toxicokinetics of metallic wear and corrosion products within the surrounding bone tissue. For their detailed analysis, the researchers
used a unique synchrotron-based X-ray fluorescence imaging setup. "Our
work has enabled us to show, for the first time, that both particulate
and dissolved metals released from arthroplasty implants are present in
the surrounding bone and bone marrow at supraphysiological levels," says
Dr. Geissler. "Therefore, the collagen-rich layer which encapsulates
the implant after surgery does not separate these metals from human
tissue to the extent previously assumed." The researchers collected
minute bone and bone marrow samples from 14 patients undergoing either a
hip or knee arthroplasty procedure. The researchers then determined the qualitative and quantitative composition of the samples using a technique
known a X-ray fluorescence. This technique provides unique insights into
the concentration, distribution, location and accumulation of metallic degradation products like cobalt, chromium or titanium in adjacent bone
and bone marrow. The extremely bright and intensively focused X-ray beam required was achieved by the synchrotron radiation source at the European Synchrotron Radiation Facility (ESRF). The ESRF, which is located in
Grenoble, France, is the only particle accelerator in the world to offer
a spatial resolution of up to 30 nanometers. Summing up the researchers' achievements, the study's first author, Dr. Janosch Schoon, says:
"Our work therefore addresses an issue of enormous clinical relevance
with a highly complex experimental setup." "Our study has made a major contribution to the improvement of the risk-benefit evaluation of medical devices. It has shown that these evaluations should not only comprise biocompatibility testing of raw materials; rather, biocompatibility
testing should also extend to wear and corrosion products. The data
from this study will therefore prove instrumental in keeping implant
safety at the highest possible level," explains Dr. Geissler. Based
on their findings, the researchers plan to conduct additional studies
which will investigate the biological consequences of metal release on
bones and bone marrow. At the same time, the researchers will develop
new approaches which will facilitate the reliable preclinical testing
of implant materials using both human cells and engineered tissues.


========================================================================== Story Source: Materials provided by
Charite'_-_Universita"tsmedizin_Berlin. Note: Content may be edited for
style and length.


========================================================================== Journal Reference:
1. Janosch Schoon, Bernhard Hesse, Anastasia Rakow, Melanie J. Ort,
Adrien
Lagrange, Dorit Jacobi, Annika Winter, Katrin Huesker, Simon Reinke,
Marine Cotte, Remi Tucoulou, Uwe Marx, Carsten Perka, Georg N. Duda,
Sven Geissler. Metal‐Specific Biomaterial Accumulation in
Human Peri‐Implant Bone and Bone Marrow. Advanced Science,
2020; 2000412 DOI: 10.1002/advs.202000412 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/08/200811120050.htm

--- up 3 weeks, 6 days, 1 hour, 55 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1337:3/111)