It's far from career ending but generally wipes out a season. It's if there is a recurrence (2-3% overall but probably higher in professional sportspeople) then it can become a career ender. There's a much higher incidence of ACL injuries in women's football due to the angle of their knee based on their wider hips (according to my physio).
The surgery is very advanced and is very common, as I mentioned earlier there are loads of papers regarding the placement of the graft and research into the benefits of each graft type, but considering most ACL injuries don't involve contact they don't really know why they really occur initially which makes it difficult to attempt to prevent recurrence anyway.
There's loads of collateral damage that can also occur when the ACL ruptures as the knee can move into an unnatural position putting stress onto the other ligaments and the meniscus (the shock absorbers of the knee). One of the worst is the unhappy triad where you tear the ACL, the MCL and also damage the medial meniscus (the one on the inside). Sometimes the meniscus damage is picked up on an MRI but othertimes if it's a bucket handle tear it can't be confirmed until surgery. I had a partial MCL tear as well as the full rupture of the ACL bit thankfully no meniscus damage. I did however have a lot of bone bruising seeing as the unnatural twisting motion was stopped by bone hitting bone rather due to the ACL not doing its job. Took ages for me to be able to bend that knee any significant amount. I had to work on this before surgery. So sometimes it's best not to operate straight away after an injury occurs also, if they do and the rest of the knee is not in a good state it won't ever recover fully. With Botman there wouldn't have been any other damage when the initial injury occurred so operating right away (with hindsight) would have been the best option.
It seems strange when they get the decision wrong at that level, but it makes sense when you consider all factors at play. Now I hope that noone who is medically trained reads any of what I have posted as they're likely to tell me it's a complete load of shit.