Abstract
BACKGROUND: Pediatric anterior cruciate ligament injuries have increased over the past two decades. Surgical reconstruction is often necessary to restore joint stability and prevent secondary injuries. Physeal-sparing anterior cruciate ligament reconstruction is commonly used in prepubertal patients to minimize the risk of growth disturbances. However, this technique has also been used for adolescents. The effect of age on joint stability and tissue function following physeal-sparing reconstruction remains unclear. This study aimed to compare initial biomechanical outcomes of physeal-sparing reconstruction within juvenile and early adolescent porcine joints. METHODS: Twelve porcine hindlimbs (n = 6 per age group) were tested using a robotic testing system. Anterior-posterior loading, compression loading, and varus-valgus torque were applied to the tibia in the intact, anterior cruciate ligament transected, and anterior cruciate ligament reconstructed states at 40° and 60° of flexion. Soft tissue forces were calculated by the principle of superposition. FINDINGS: Physeal-sparing reconstruction in early adolescent joints resulted in superior anterior stability under anterior tibial loading and compression compared to juvenile joints, especially when normalized for joint size. Medial collateral ligament distraction and medial meniscus compression contributions showed smaller changes following reconstruction in the early adolescent group at 60° of flexion. Other joint kinematics and tissue forces were similar between groups. INTERPRETATION: These findings suggest that skeletal maturity influences joint stability following physeal-sparing anterior cruciate ligament reconstruction, supporting its viability for both younger and early adolescent patients. This study provides biomechanical insights into surgical treatments for young patients and underscores the importance of using age-specific models to evaluate pediatric surgical techniques.