Abstract
Background The anterior cruciate ligament (ACL) rupture is a common injury with an incidence of 68.6 in 100,000 patients per year. Despite extensive research on ACL rupture, there are insufficient high-quality studies to determine clear treatment strategies for adults lacking the ACL. This study aims to examine the functional differences between surgical and conservative treatment based on the quality of the surgical process. Methodology In this prospective, comparative study, a total of 136 patients aged between 18 and 35 years were enrolled per inclusion and exclusion criteria. Using the lottery system, patients were divided into the following two groups: group A (n = 71) and group B (n = 65). Group A was treated with arthroscopic ACL reconstruction and rehabilitation, whereas group B was treated conservatively (rehabilitation). Patient data, including age, sex, body mass index, International Knee Documentation Committee (IKDC) score, Knee Injury and Osteoarthritis Outcome Score (KOOS), Tegner Activity Level (TAL) score, and complications were recorded and compared. Results The demographic data were comparable, where males had dominancy in both groups. The mean IKDC and KOOS scores were higher in group A at all follow-ups compared to group B. The scores gradually increased at every follow-up till six months. At the final follow-up, the IKDC and KOOS scores were higher in group A than in group B, and a significant difference was observed among both groups. The TAL score also gradually increased at every follow-up till 6 months. At the final follow-up, the TAL score was higher in group A than in group B, with a significant difference between the two groups (p = 0.0032). Complications in both groups were comparable. Conclusions This study showed that both the conservatively treated group and the rebuilt group had identical outcomes, with the exception of the conservative group having greater objectively quantifiable instability. However, at the final follow-up, patients reported feeling just as satisfied with their knee without surgery, demonstrating no subjective difference in activity levels or functional outcomes. Therefore, non-athletes with an ACL-insufficient knee should still choose conservative treatment.