Biomechanical Evaluation of Fixation Techniques for Posteromedial Tibial Plateau Fractures: A Cadaveric Model

Abstract

Objectives: This study aims to compare the biomechanical performances of five fixation techniques, posteroanterior (PA) screw, anteroposterior (AP) screw, posterior locking compression plate (LCP), anatomic posteromedial plate (PMP), and anterolateral plate (ALP), for isolated posteromedial tibial plateau fractures using cadaveric models under static and dynamic axial loading conditions. Materials and methods: Twenty-five fresh-frozen cadaveric tibias were used to create standardized posteromedial split-type fractures. Specimens were divided equally into five groups based on the fixation method. Biomechanical testing involved cyclic axial loading (10-250 N, 2500 cycles at 2 Hz), followed by loadto-failure testing under static compression. Outcome parameters included stiffness, load at 3 mm displacement, ultimate load, displacement at failure, and photographic displacement. Results: The PMP group demonstrated the highest biomechanical stability, with the greatest ultimate load (805.60 +/- 218.96 N) and minimal displacement. The PA screw fixation also showed acceptable performance, offering a minimally invasive alternative. In contrast, the AP and ALP groups exhibited the lowest values for load tolerance and fragment control. There were significant differences between the groups, particularly favoring posterior-based techniques (p<0.05). Conclusion: Anatomic PMP provides superior biomechanical stability for isolated posteromedial tibial plateau fractures. The PA screw fixation offers a less invasive, yet stable alternative. Anterior-based fixation strategies such as AP screws and ALP should be avoided due to biomechanical insufficiency.