Anterior Cruciate Ligament Reconstruction and Injury Risk after Second Reconstruction Surgery in Adolescents

Background: Anterior cruciate ligament (ACL) tears are a common knee injury in younger populations, that can re-occur following ACL reconstruction (ACLR). Approximately 10-16% of children with a primary ACLR require revision, but the portion of pediatric patients which require an additional ACLR after a second procedure is unknown. This study aims to report the risk of a third ACLR and other knee injuries in adolescents at several time scales following the second ACLR. Objectives: We hypothesized that the risk of an additional ACLR procedure after a second procedure would be similar to the published risk of requiring a revision procedure after the primary ACLR. Methods: Retrospective analysis of the TriNetX database was performed. A cohort was created of adolescents ages 10-19 who sustained an ACL tear and underwent 2 separate ACLR procedures spaced by 9 months following their injury, stratified by injury laterality. Demographic variables were measured, and risk of outcomes were noted at 1 year, 2 years, and 5 years following the second ACLR, including subsequent ACLR, ligamentous and meniscus tears, and other knee pathologies such as chondromalacia patella, osteoarthritis, and arthrofibrosis. For comparison, these steps were repeated for a cohort of adolescents who sustained an ACL tear but only underwent one ACLR procedure. Results: A total of 681 and 673 patients were identified who underwent revision ACLR after a right and left ACL tear and primary ACLR, respectively. Mean age was 16.9 ± 1.5, with most patients being female and White. Risk of subsequent ACL revision was 3.3% within 1 year, 6.8% within 2 years, and 8.5% within 5 years. These patients also had a 9.5% risk of requiring meniscal repair or resection, 2.5% risk of medial collateral ligament tear, and negligible risk of posterior cruciate or lateral collateral ligament tears at 5 years. Conclusion: Pediatric patients who have undergone a revision ACLR have a 1 in 11 risk of requiring an additional ACLR procedure, and slightly higher risk for requiring meniscal surgery, within 5 years. Our findings can be used to counsel patients considering revision ACLR on their risk of returning to the operating room and developing further injury following surgery.