At what age are we talking?
Well, in middle age, it accelerates and accelerates MORE past that. For example, at 50 or so, you will definitely notice the difference and after that, this accelerates more and more with advancing age.
The process starts GRADUALLY when one is younger though. So, late 20's or so, it's not noticeable and on subtle side in 30's. In 40's the changes get more noticeable.
Basically it is SAME as aging process; gradual in 20's and not so noticeable but after 40, it goes from noticeable to very noticeable in terms of acceleration of the aging process over time.
ETA: Just to say, the implant itself, may remain constant but the biological material (your bones and flesh) change around it.