Study Selection: Available studies were included only if they were written in English; were of level 1, 2, or 3 evidence (grading taxonomy not stated); were cohort designs that compared nonoperative and operative treatments; involved an early versus delayed ACL reconstruction that could be prospective or retrospective; and reported primary outcome interest measures. Animal studies, basic science studies, case series, reviews, commentaries, and editorials were excluded from the review.Data Extraction: A systematic assessment tool, Guide to Community Preventive Services: Systematic Reviews and Evidence-Based Recommendations, was used by 2 of the authors to independently grade the quality of each study that met the inclusion criteria. The tool focused on 6 areas: intervention and study description, sampling, measurement, analysis, interpretation of results, and other execution factors. This tool helped to ensure consistency, reduce bias, and improve the validity and reliability of preventive health care studies. Eleven studies met the inclusion criteria. Six studies compared nonoperative with operative treatment, and 5 studies compared early reconstruction (open physes) with delayed reconstruction (closed physes). Studies in this meta-analysis consisted of the following: four level-3 prospective studies, four level-3 retrospective studies, one level-2 retrospective study, one level-3 case-control study, and one level-3 study with both prospective and retrospective data collection. All of the studies included data related to patient demographics, treatment interventions, follow-up duration, presence of any meniscal symptoms, time to return to sport participation, patient-reported outcomes (International Knee Documentation Committee [IKDC], Lysholm, or Tegner scores), the need for a second surgical procedure, and any posttreatment problems.Main Results: Of those who chose the nonoperative route, 75% reported instability, whereas only 13.6% of those who had surgery reported instability. These data also showed that nonoperative or delayed-operative patients were 33.7 times more likely to report instability than the early operative group. Those who chose the nonoperative route had a 12 times greater risk (odds ratio ¼ 12.2, 95% confidence interval ¼ 1.55, 96.3) of developing a meniscal tear after the initial injury. Three studies included in the meta-analysis reported return to sport status, but only 2 studies provided adequate data for both operative and nonoperative patients. In 1 study, 92% of operative patients were able to return to sport, but only 43.75% of nonoperative patients were able to do so. The second study reported that all operative and nonoperative patients were able to return to the same level of sport after injury. Of those in the early operative group, 6% required a repeat surgical intervention for either an ACL rerupture or a meniscal tear, and 19% of those who initially chose nonoperative treatment eventually needed surgery to repair the ACL or meniscus. Findings favor the early operative group ove...