Primary Questions:. Does ACL reconstruction prevent osteoarthritis?Who are the appropriate candidates for ACL reconstruction?. Secondary Questions:. Is there anything better on the horizon?. Who is a candidate?. Age:1987-Kannus and Jarvinen conservatively treated patients mean age 32 years, mean follow-up 8 years-poor results in non-operative treatment1994-Ciccotti et al reported 83% satisfaction in patients mean age 46 treated conservatively. Pt's required to modify activity .