Biomechanical comparison of porous fusion cages and fixation plates for high tibial osteotomy using finite element...

High tibial osteotomy (HTO) is a joint-preserving procedure for medial compartment knee osteoarthritis, in which fixation device selection is critical for initial stability and bone healing. This study aimed to compare the mechanical performance of three HTO fixation systems: Solid HTO Fusion Cage (S-HTOFC), Porous HTO Fusion Cage (P-HTOFC), and Medial HTO Fixation Plate (M-HTFP). Patient-specific finite element models were constructed from postoperative CT data of a 55-year-old male with bilateral medial compartment osteoarthritis (Kellgren-Lawrence grade III). Two loading conditions (standing and sit-to-stand) were simulated to evaluate overall displacement, wedge micromotion, von Mises stress distribution, and fatigue life. P-HTOFC showed the smallest displacement under both loading conditions, reducing maximum displacement by 60.7% and 68.5% versus S-HTOFC and M-HTFP during standing. P-HTOFC exhibited superior wedge gap stability, more uniform stress distribution, and an 84.3% reduction in average stress compared to M-HTFP. Lateral hinge stress was reduced by 77.2% relative to M-HTFP, lowering fracture risk. Fatigue life in the posterior screw-hole region was more than 18 times greater than M-HTFP. The Porous High Tibial Osteotomy Fusion Cage outperforms traditional internal fixation plates in overall mechanical performance, demonstrating better stability, more uniform stress distribution, and longer fatigue life, suggesting strong potential for clinical application.