Metal-Metal Articulation by Dr. Schmalzried
CCJR Debate February 10th, 2013
Dr. Schmalzried explained that
"The benefits of metal-metal
are well known: high stability because of the large diameter, low
wear potential, and they are unbreakable. The thin monoblock sockets
allow for resurfacing with acetabular bone conservation. One of the
risks is a higher loosening rate … Another is
that there is position sensitivity. In addition, metal particles,
ions, corrosion products, adverse local tissue reactions are a
problem as well."
…"The Australian data indicates that loosening is the problem, as
opposed to adverse local tissue reaction. Don’t think that I’m not
concerned about the latter, but loosening is associated with the
larger heads and the monoblock sockets. In this registry the cause
of revision is 0.5% metal sensitivity…"
"In the 2010 Australian National Joint Registry they had greater
than 96% five-year survival of modular metal-metal constructs. Large
is forgiving … for stability. But it is no more forgiving of position.
There are growing numbers of studies showing that if you have a
metal-metal bearing … that has a lateral opening angle of
greater than 50-55 degrees then you are likely to have a wear
"The majority of my metal-metal experience is with hip
resurfacing. The patients I care for are unaccepting of disability
and they want no restrictions. The requirements include substrate
strength, range of motion and stability, low wear and revisability.
There are learning issues, but Treacy’s experience (2010) shows 98%
10-year survival for males and 96% 10-year aseptic survival for all
comers. In the 2010 Australian registry they had greater than 96%
survival in males younger than 65 with osteoarthritis, and greater
than 96% survival when you have a large patient."
"In my opinion the benefits still outweigh the risks in