Robbo
Paul Walsh
I suppose I'm thinking mostly of Owen, Essien, Gazza, Bullard maybe and Fowler - maybe even Anderson who is struggling to get back to fitness.
People like Xavi, Van Nistelrooy, Pires and Keane have done well after an ACL. I guess rehab may be even more advanced now but I suspect it depends how bad the injury was (what grade) and how many other knee ligaments were affected.
Not to mention me, who suffered an ACL tear in 2005. My knee got better in the end, but within a few years I was diagnosed with runner's knee. Today any form of running or football will make my knee swell up.
I'm not at all comparing myself to top athletes, but the last diagnosis I had, was definitely connected to the ACL tear and subsequent operation - which was successfully performed by this internationally reknowned ACL surgeon: http://www.osv.com.au/page.asp?lvl=2&id=6
So there is definitely a risk involved. Knee surgery is serious business.