An approach to the ruptured anterior cruciate ligament Up to 70 percent of most anterior cruciate ligament accidents occur in a non-contact environment through a pivot or cutting motion al reviews . When should medical reconstruction be considered for ACL injuries? Isolated anterior cruciate ligament injuries take into account up to fifty % of all ligamentous accidents to the knee and have been reported that occurs in an approximated 1 in 3000 people in the overall population. However, as 95 percent of ACL accidents occur in people between the age groups of 16 and 45, the recalculated incidence in this age group is 1 in 1750 people.