The purpose of this study was to investigate possible differences in age, gender, Tegner activity level prior to injury, knee joint laxity and the variables evaluated with knee osteoarthritis outcome score (KOOS) between patients who chose non-operative treatment (NT), early reconstruction (ER) and late reconstruction (LR). A second aim was to study whether patients who choose ER choose surgical treatment for the same reasons as patients who choose LR. Seventy-two patients with an acute (< 1 month) anterior cruciate ligament (ACL) tear, who had not yet decided to have surgery, were included in this study. They filled out the Tegner activity score, assessing preinjury activity level, KOOS and underwent KT-1000 arthrometer examination. The 36 subjects who later chose reconstruction were questioned about reasons for their decision. A high preinjury activity level was associated with the choice of ACL reconstruction, but the choice of treatment was not associated with age, gender or the outcome variables measured with KOOS or KT-1000. Fifteen out of the 20 (75%) subjects who chose ER based their decision on assumptions of future problems and not on experience of knee function. Fourteen out of 16 (88%) subjects, who chose reconstructive surgery later, based their decision on experience of knee function.