hoichi - yeah my dad had a hernia repair too a few years back.
Mine is considered congenital possibly related to prematurity.
hopefully your luck at avoiding hernia will hold! <hand knocks on wood for you too!>
Current and more holistic thinking about the cruciate issue in dogs and in many ofg the bigger and more muscular breeds, is that it's actually a disease - the end result of a combination of things - one - genetic/breed tendency including structural deficit in the knee joint - is related to, or causes - inflammation in the knee, making it more prone to be weak and stressed. This you don't see yet - until the point at which the ligaments - like in a rope- start to fray. There's your tear and then the dog may start to intermittently limp, or have a sudden- appearing incident when she's running or doing something physical like doing a back rub on the carpet <belly up, like a horse rolling> and she kicks out one of her hind legs and cries. Both of these things happened and that led us to take her to our primary, Western vet, who was suspicious of the problem. I then took her to a vet who is also a certified canine rehab speciallist <additional training in canine sportsmedicine and rehab> who saw her walk and said she was lame <to me by that point her lameness was not visibly noticeable>.
So we did x-rays and found joint changes in the knee and fluid on the joint which is a sign of a partial cruciate injury.
This all happened before my surgery.
This is my youngest, crazy ball-playing, high-drive working dog.