• Both Kirschner wire internal fixation and splint external fixation effectively maintain stability of Salter-Harris type II distal radius epiphyseal fractures.
• The two fixation methods show similar biomechanical performance in reducing displacement and stress at the fracture site and distal radioulnar joint.
• Finite element analysis provides quantitative biomechanical evidence for treatment selection in pediatric distal radius epiphyseal fractures.
• Splint external fixation may be a viable alternative to Kirschner wire fixation, potentially reducing surgical risks.