There are many variables when it comes to deciding if a patient should undergo ACL reconstruction. These include age, activity status, concurrent cartilage tears, and feelings of instability with activities of daily living, work, and leisure activities.
In general, I recommend ACL reconstruction for teens(sometimes younger) through age 40. After 40, if the patient is very active in pivot sports or has instability I would recommend repair. The ACL is a protective ligament for the meniscus cartilage and provides stability to the knee. As our life expectancy continues to climb, I expect ACL reconstruction to be recommended, routinely, for those over 40.