On Wed, 16 Mar 2005 10:04:29 -0800, Larry Jaques
wrote:

On Wed, 16 Mar 2005 07:37:24 -0800, the inscrutable Eric R Snow
spake:

I noticed that ring thing when I had an MRI years ago. But recently I
had another and now there's a bunch of stainless and titanium in me. I
guess because it's all screwed in place there was no discernable
vibration.

You might be the person to ask about this, Eric. I have a new neighbor
who has a titanium hip and ball joint. His left leg is 2.5" shorter
than the right, and he's on his FIFTH hip. Is there any reason you can
think of (other than lousy doctors) which would make frequent
replacement necessary?


-
Yea, though I walk through the valley of Minwax, I shall stain no Cherry.
http://diversify.com
Yes, I studied implants and their effects on the human body.
Specifically wrists, but the hips act the same. Here's what happens:
No matter what the implants are made of and how non-allergenic the
materials are small particles are shed from wear. There are cells
called osteoclasts and osteoblasts. The osteoblasts build up bone and
the osteoclasts destroy bone. These cells must work in concert to keep
renewing bone. The small particles cause inflamation, an immune
response, just because of their size. This causes the osteoclasts to
be more active than the osteoblasts and bone will be lost in the area
where the implant is anchored in the bone. This causes the implant to
loosen which makes things worse. Surgery to correct the problem works
by removing bad bone and setting a new, larger implant in an enlarged
socket. I imagine if the femur is too wallowed out the only way to get
to good bone is by removing some length as well as opening up the
socket. This could happen because the socket is tapered, at least they
were in the ones I've seen. Hope that explains it. I can be long
winded.
Eric