Purpose <p>The Both Column Screw (BCS) fixation technique is a recently introduced, innovative method for the treatment of acetabular posterior column fractures. This study aims to biomechanically compare the BCS technique with conventional posterior column lag screw fixation methods using finite element analysis.</p> Methods <p>Five different internal fixation models were simulated using five distinct screw fixation techniques: antegrade posterior column screw (APCS), retrograde posterior column screw (RPCS), magic screw (MS), anterior BCS (aBCS), and posterior BCS (pBCS). The modeling process included meshing, assignment of material properties, and definition of boundary conditions. Each model was subjected to three different loading conditions: level walking, stairs up, and stairs down. The biomechanical performance of each fixation technique was evaluated based on five parameters: maximum stress in the screw, maximum stress in the bone, total deformation, gap in fracture surfaces, and sliding distance in the fracture surface.</p> Results <p>Finite element analysis demonstrated biomechanical differences among the five fixation techniques. The APCS model consistently showed the highest stress values and deformation across all loading conditions, whereas the MS, aBCS, and pBCS models exhibited lower deformation and stress parameters. Among these, pBCS generally displayed the most favorable performance in terms of stress reduction and fracture stability. Overall, the BCS configurations (aBCS and pBCS) showed improved biomechanical behavior compared to conventional fixation methods.</p> Conclusion <p>The BCS fixation technique, due to its superior biomechanical properties, may serve as a valuable addition to current methods for acetabular posterior column fractures. It broadens surgical options and may support clinical decision-making for orthopaedic surgeons.</p>