From simulation to sideline: translating finite element modeling into clinical decision-making for pediatric ACL injury and rehabilitation.

Anterior cruciate ligament injuries in children and adolescents are rising, and young athletes remain at high risk for reinjury, graft failure, and early joint degeneration despite advances in reconstruction and rehabilitation. A major barrier to improving outcomes is the lack of tools that can noninvasively quantify internal knee mechanics, tissue loading, and the biomechanical consequences of surgical and rehabilitation choices in growing patients. In this narrative, we synthesized emerging work on subject-specific finite element modeling of the pediatric knee and integrated it with clinical knowledge of anterior cruciate ligament injury and management. Drawing on peer-reviewed work from multiple groups, we emphasize pediatric and adolescent applications of these modeling approaches. Rather than presenting new data, we use representative studies to illustrate how validated models have been constructed, evaluated, and applied to clinical laxity testing, ACL reconstruction variables, movement-specific ligament loading, orthotic assessment, and rehabilitation decision-making. We then highlight the striking imbalance between adult and pediatric knee modeling, emphasizing key limitations such as reliance on adult soft tissue material properties, sparse age-specific validation data, and fragmented workflows for integrating imaging, motion analysis, and simulation. Building on these insights, we propose a translational framework that links model outputs directly to clinical decision points in pediatric sports medicine, including surgical planning, brace and orthosis prescription, and return-to-sport assessment. We conclude by outlining a roadmap toward pediatric digital twin systems, in which rigorously validated, patient-specific simulations become routine tools to personalize treatment, reduce reinjury risk, and protect long-term joint health in young athletes.