A37-18 Assessing the Impact of Biologic Augmentation on Sternal Fixation Stability: A Finite Element Analysis

Abstract Objective The use of biologic materials in sternal closure procedures is often underutilized. Prior evidence suggests that augmenting traditional fixation methods with biologics can enhance postoperative stability and promote bony union. This study investigated the biomechanical performance of two common sternal closure techniques—stainless steel wire and titanium plate fixation—under various loading conditions, both with and without a bone graft. The primary objective was to assess whether graft augmentation improves stability under lateral distraction, shear, and torsional forces, thereby enhancing load-bearing capacity and reducing failure risk. Methods Finite Element Analysis (FEA) was performed to replicate the biomechanical environment of post-sternotomy closure. A three-dimensional sternum model was reconstructed from CT data, representing a midline sternotomy fixed with either stainless steel wires or titanium plates. A 4mm synthetic bone graft was incorporated between the sternal halves in augmented configurations. Physiologic loading conditions—including lateral distraction (respiration), shear (asymmetric muscle or arm movement), and torsion (twisting)—were applied to simulate postoperative stresses. Outcomes included load distribution, displacement, construct stiffness, and graft-sternum interface behavior. Results Integration of the bone graft significantly improved biomechanical stability across all configurations. In wire fixation, graft augmentation enhanced shear stability by over 100% and torsional stability by 75%. For plate fixation, the graft increased lateral distraction resistance by 26%. Graft inclusion also eliminated interface slippage and improved uniformity of load distribution across the sternum. Statistical analysis confirmed significant differences for wire + graft under lateral distraction and torsion (p 0.0001). These results indicate that the graft functions as both a mechanical bridge and a load-sharing interface, enhancing overall construct stability. Conclusions Incorporating a synthetic bone graft into standard sternal closure techniques markedly enhances mechanical stability, reduces displacement, and minimizes slippage at the graft-sternum interface. Both stainless steel wire and titanium plate fixations demonstrated improved performance when augmented with the graft. These findings highlight the clinical potential of biologic integration in sternal repair, particularly in patients at risk for dehiscence or poor healing. By improving load distribution and construct stiffness, graft augmentation may provide a more reliable and stable closure method, supporting faster recovery, reduced complications, and better postoperative outcomes following median sternotomy. This abstract is funded by: None