MATHEMATICAL JUSTIFICATION OF RESTORATION OF THE ACROMIO-CLAVIVICULAR JOINT BY A NEW COMBINED METHOD

Introduction. In the development of implants for osteosynthesis, specialists increasingly use mathematical (computer) modeling to biomechanically justify the advantages, strength characteristics, and reliability of implants in practical applications. Mathematical modeling enables the extraction of the maximum useful information to ensure the mechanical compatibility of the implant.

Objective. To study the stress-strain state in the biomechanical systems «clavicle – hook-shaped plate» and «clavicle – hook-shaped plate – lavsan tape» using the finite-element method using the KOMPAS-3D (APM FEM) program and Autodesk Inventor PR.Materials and methods. The article presents the results of the mathematical justification of the restoration of the acromioclavicular joint by a new combined method (Patent for invention RK No. 36128 dated 03.03.2023 «Combined method for restoring the acromioclavicular joint»).

Results. The finite-element method using the KOMPAS-3D (APM FEM) program and Autodesk Inventor PR was used to perform a mathematical analysis of the stress-strain state under the influence of excessive loads in the biomechanical systems «clavicle – hook plate» and «clavicle – hook plate – lavsan tape». An averaged virtual stereolithographic 3D computer model of the clavicle and scapula (STL model) was developed to implement the task.

The finite element analysis showed that the new combined method reduces equivalent stresses from 8.16 to 4.19 Mpa, decreases the displacement of the hook from 1.5 to 0.03 mm, and increases the minimum safety margin from 1.74 to 1.93.

Conclusion. The conducted biomechanical studies revealed the advantages of the new method for restoring the acromioclavicular joint over the classical method of splinting using a hook-shaped plate. The new method reduces stress at the points of interaction between the hook of the hook-shaped plate and the acromial process of the scapula by 1.9 times, decreases the displacement of the hook by 50 times, and increases the safety margin for 1 min.

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