Fixation of Extra-articular Proximal Tibia Fractures: Biomechanical Comparison of Single and Dual Implant Constructs

Objectives: This biomechanical study seeks to define the relative effectiveness of contemporary single and dual implant constructs for fixation of an extra-articular proximal tibia fracture model. Methods: An extra-articular proximal tibia fracture model was created using synthetic tibias. Four constructs were tested. Constructs included (1) lateral locked plate (LLP), (2) intramedullary nail (IMN), (3) combined LLP and IMN (PN), and (4) LLP and medial locked plate. Specimens were axially loaded through the medial plateau to evaluate construct stiffness and the ability to resist varus collapse. Results: Dual implant constructs were stiffer than single implant constructs in this model. Although DP and PN were stiffer than IMN at all loads tested, the difference was notable only for DP at higher loads. Isolated LLP provided insufficient stability to be tested at higher loads. Conclusion: Dual plate fixation provides the greatest resistance to varus collapse. In the clinical setting, consideration must be given to the fracture morphology, desired construct stiffness, and soft-tissue envelope in selecting the optimal construct to be used.