An anterior cruciate ligament tear in the knee is a devastating injury and does result in knee instability in most cases. The current scientific evidence suggests that a reconstruction will restore knee stability but only about two thirds of patients are able to return to their previous activity., There are increasing comments that with appropriate physiotherapy surgery can be avoided. This may well be true for the copers who can return to their activities without an ACL. But be aware these are only approximately 5% of all injured patients. The other 95% have to either reduce their activities and adjust to their unstable knee or have surgery. The big dilemma here is that we do not really know what the natural history of a chronic unstable ACL deficient knee is. What we know is that ACL deficient knees are susceptible to meniscus injuries and this will results in osteoarthritis- sooner or later. So who does not need surgery? Patients with partial tears and no instability, complete tears with no instability and low demand sports, patients who are willing to give up high demand sports and patients who do light work or lead sedentary lifestyles potentially do not require a reconstruction. So who needs surgery? Patients participating in active sports with pivoting and turning movements, manual workers, patients with significant functional instability, patients with a repairable meniscus lesion and patients with the so called unhappy triad of ACL tear, meniscus tear and medial collateral ligament injury should consider to undergo a reconstruction. If you have any of these symptoms contact us and make an appointment with a fellowship trained surgeon in Orthopedic Sports Medicine.