Why implants loosen/fail over time
- Thread starter Simon
- Start date
- Status
United States
Judles
alpha
Uh ......yeah,right!!! Sure ya do, Mr. Mark!!! (
0). I guess you and Judy have been discussing it nightly just like Jay and I. (????). Yikes!!!! Hope you're having a good day, kiddo! You know I gest!!! (0)
0). I guess you and Judy have been discussing it nightly just like Jay and I. (????). Yikes!!!! Hope you're having a good day, kiddo! You know I gest!!! (0)
matalie
new member
When the surgeon implants a knee or hip, they will creat a very intimate fit between the implant and the bone, either by cementing the part in place or using a slightly larger, roughened one (press fit). The bottom line is that over time the polyethylene (plastic) insert will wear and the microscopic wear particles will be in the joint fluid that washes throughout the hip or knee joint. These particles are attacked as foreign bodies by the immune system and removed from the joint. Unfortunately, these particles are approximately the same size as bone cells that the implants are attached to. As the body attacks the plastic wear particles, it can't differentiate and attacks the bone cells as well. This process causes the surface area of the bone where the implant is attached to break down and the intimate fit of the implant to bone is disrupted, causing loosening. This process is known as aseptic (absence of infection) osteolysis (osteo=bone, lysis=destruction). This is the typical reason the implants will loosen. The companies are working very hard to come up with materials that won't wear (thus ceramic and metal bearings), but all materials as of now have issues.
The picture below shows how the once tight fit on the bottom end of the stem is now a large opening, as the bone inside the femur has been resorbed. You can see that the bone on the greater trochanter (upper right of the pic) is gone, allowing the joint fluid to flow down into the femur.
This is what it should look like-tight fit of the bone along the length of the hip stem
Hope this helps explain...
The picture below shows how the once tight fit on the bottom end of the stem is now a large opening, as the bone inside the femur has been resorbed. You can see that the bone on the greater trochanter (upper right of the pic) is gone, allowing the joint fluid to flow down into the femur.
This is what it should look like-tight fit of the bone along the length of the hip stem
Hope this helps explain...
SissyG
senior
Boy, I read the easy to understand version and thought to myself....:shk:HUH!
Was I ever relieved when I starting reading all the posts and found out that nearly everyone else was as lost as I was with the explanation...my PKR is on September 21st so for now I am going to think positively stay in the dark about what is in the article and not try to figure out why they might possibly fail...Sissy
Was I ever relieved when I starting reading all the posts and found out that nearly everyone else was as lost as I was with the explanation...my PKR is on September 21st so for now I am going to think positively stay in the dark about what is in the article and not try to figure out why they might possibly fail...Sissy
cindy88fan
supremo
Sissy,
That is a great idea. Why worry about something that probably won't happen. If it does...then worry!
That is a great idea. Why worry about something that probably won't happen. If it does...then worry!
Clunker
post-grad
Hi Sissy,
I like the way you think,
I like to stay in the dark also,:hehe:
Very good luck on the 21st:thmb:
calling_all_angels
big-cheese
Hot digg-a-dee that was great Matalie!!!!
Thanks ever so much!!!! Tomorrow when
My head clears I 'm going to ask you a few
questions ok??? You explain things so even
I abie-normal could understand!!!
Thanks ever so much!!!! Tomorrow when
My head clears I 'm going to ask you a few
questions ok??? You explain things so even
I abie-normal could understand!!!
- Status
