I wonder about torn connective tissue. The weakest link idea probably applies there. So many people have problems with their knees. In Australia they have a woman's game called netball. The gals stop suddenly all the time and often play on road like surfaces. Many end up needing knee surgery. Who knows when the damage is done or if things accumulate over the years.
Arthritis is another thing that is a worry. I am more or less free of that but my fingers do feel stiff at times. Who doesn't have a sore back from time to time! At 20 we feel invincible and don't listen to stories about the dangers of lifting weights. I paid the price because I tore my right biceps doing a 509 pound deadlift when I was about 35. Curses. I never could totally straighten my arms so maybe that contributed. Nowadays I tell people to avoid dead lifts and never do less than 5 reps. They don't listen. If Ronnie Coleman does them then they do them. Lunacy. You would think that guys like me with 55 years experience bodybuilding would be listened to but muscleheads use their own brains which is foolhardy.
I spent a lot of my adult life trying to overcome my twink teenage body. For reasons I cannot explain, I don't think I ever went crazy lifting poundage that my body was not built to safely lift. I spent years trying to fulfill the dream of being huge. I never achieved this goal really, although I had a moment when it seemed like I had when I was 29 years old.
There are a lot of theories as to what causes arthritis. I have not heard or read anything which suggests it is caused by lifting weights. Everything I've read suggests that weight resistance exercises actually decrease the negative affects of arthritis.
As for my torn meniscus, I believe it was absolutely not caused by lifting. I have been fortunate in that I have always went for strict and clean lifts over heavy sloppy ones. I have reached the conclusion that it is simply a result of being old. As we age, things break down. Apparently my meniscus could be one of these breakdowns. Interestingly, I once suffered knee damage when I was still a teenager and was dancing, doing the twist. I popped my knee out and immediately popped it back in. The next day it was ridiculously swollen and sore. As do most young folks I easily recovered from this injury. I suspect it is no coincidence that this is the same knee that I recently had surgery on.
I suspect you have been much more devoted to bodybuilding then I have been. While I had goals to overcome my early twink build, I never aspired to be a competitive bodybuilder. I have always been something of a health nut though. I think this approach to lifting has served me well for the most part.
If you read through my posts, you will discover that I am currently on HRT. I have no doubt this contributes to the success of my retaining something resembling a youthful and masculine physique. Like with everything in my life, I approach HRT with moderation. Needless to say, I am not shooting huge amounts of test every week, just 200 mg.