Predicting anterior tibial translations in pediatric ACL-deficient knees with finite element knee models

Anterior cruciate ligament (ACL) injuries frequently occur in young individuals. However, knee biomechanics in this population, especially among adolescents, are poorly understood. The purpose of this study was to use finite element (FE) knee models to investigate anterior tibial translations during the Lachman test (LT) and pivot shift test (PST) in ACL-deficient pediatric knees. Computed tomography scans from 22 subjects (aged 9-18 years; 6 females, 16 males) were used to create FE knee models. Cadaveric, experimental data of ACL-deficient knees were used to validate the accuracy of the models' anterior tibial displacement predictions. Simulated anterior tibial translations for the LT (21.2 mm at 134 N) and PST (7.0 mm) showed no significant differences from the experimental cadaver results (p = 0.37; p = 0.46), confirming model validity. Comparisons with ACL-intact, baseline models revealed significantly increased anterior tibial displacements in ACL-deficient knees under identical loading conditions (p < 0.001), emphasizing the ACL's stabilizing role in both translation and rotational mechanics. The study demonstrates the use of FE methods to simulate physiologically relevant pediatric knee biomechanics and highlights their potential as a preclinical tool for evaluating the biomechanical effects of surgical techniques and rehabilitation interventions. In doing so, this study provides insight into the development of personalized treatment strategies, further supporting clinical advancements in this understudied demographic.