Trevor Knight as a ref of some sort will surely know about Cruciate Ligament damage.
Very common in footballers. If you damage that lateral ligament you will probably have permanent damage, with operations needed in the future, you are gonna need an op! If you don't you will suffer.
Anyway, yes, after 10 - 15 years climbing ladders, I started getting bad knees and feet.
It is significant that I started w/c at 32, so not a teenager, I was average fitness for a 32 year old, doing ladders and all the dangerous trick with them, and by about 45 getting problems with knees and feet that I could not ignore. I tried everything, so don't tell me.
I don't want to turn this into the usual wfp/trad but, if it wasn't for wfp I would be doing bungalows only. Ladders had finished me.
My advice, if you are young...If you want to stay on ladders thats ok, but you better do some serious extra regular training for fitness, because those knees are not designed to be tensed up a ladder all day, 5 days a week for long.