I think it is a great call to skip the TMJ replacement. I used to be in the medical device / implantable device market before cancer. These things, even in perfect situations can have issues. The articular disc between the nomal condyle and the fossa over many years can wear a hole in it, and that's what keeps the two bones from rubbing against each other. It usually starts with a popping, but eventually when the hole is big enough the bones chaffing against each other becomes painful. It can (and will) eventually change people's bite, or how the cusps and fossas of their teeth mesh (interdigitate) with each other. The longer you can deal with this the better in my mind.