MATHEMATICAL (BIOMECHANICAL) JUSTIFICATION OF OSTEOSYNTHESIS FOR PROXIMAL HUMERUS FRACTURES

Introduction. Proximal humerus fractures are among the most common injuries of the musculoskeletal system. Conventional osteosynthesis techniques used in the surgical treatment of these fractures do not always provide sufficient mechanical stability, which highlights the need for the development of new biomechanically justified fixation devices.

Objective. To perform a comparative assessment of the stress–strain state of the biomechanical systems «HUMERUS – LOCKING PLATE» and «HUMERUS – NEW DEVICE» using the finite element method.

Materials and Methods. The study was conducted as a biomechanical simulation using KOMPAS-3D (APM FEM) and Autodesk Inventor Professional software. Two biomechanical systems were analyzed in the finite element model: «HUMERUS – LOCKING PLATE» and «HUMERUS – NEW DEVICE». The following loads were applied in the models: axial load F1 = 200 N, transverse load F2 = 100 N, and torsional moment M = 7.5 N · m. The loads were applied both separately and simultaneously. The evaluation criteria included equivalent von Mises stress, maximum linear displacement of system elements, and the minimum safety factor.

Results. Under all loading conditions, the «HUMERUS – NEW DEVICE» system demonstrated more favorable biomechanical characteristics compared to the locking plate. In particular, the new device showed lower equivalent stress values, reduced linear displacement, and a higher safety factor. The most pronounced differences were observed under tensile and torsional loading conditions.

Conclusion. The results of the finite element analysis indicate that the proposed device provides greater biomechanical stability than the locking plate in the osteosynthesis of proximal humerus fractures. The obtained findings demonstrate the potential advantages of the new design; however, further experimental and clinical studies are required to fully evaluate its effectiveness.

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