BIOMECHANICAL STUDY OF THE STABILITY OF OSTEOSYNTHESIS OF THE FRACTURE OF THE PROXIMAL HUMERUS BY THE DEVELOPED DEVICE IN COMPARISON WITH A STANDARD BONE LOCKING PLATE. COMPUTER MODELING BY THE FINITE ELEMENT METHOD

Abstract

Introduction. Proximal humerus fractures (PHF) are the third most common fractures after fractures of the femoral neck 
and distal metaepiphysis of the radius. PHF are most often found in the elderly and old people. Despite the availability of a 
large number of surgical treatment methods, a large number of complications are still observed, such as secondary 
displacement, screw eruption and aseptic necrosis. In this study computer modeling was carried out to determine the 
biomechanical characteristics of osteosynthesis of a PHF with a new device, and the immediate results of the operation on a 
patient are given as a clinical example. 
Research objective. Comparative study using the finite element method of computer models of the humerus, which 
fixed by the developed device and a standard bone plate. 
Materials and methods. A new device for proximal humerus fractures fixing has been developed and manufactured. 
Based on a CT scan of the shoulder joint of a middle-aged man, a 3D model of the humerus was developed. On the 
humerus models was applied simulation of 500 N compression loads along the axis and axial sharing with 200, rotational 
loads with a force of 200 N. The results of biomechanical experiments obtained during computer modeling, the distribution 
points of the maximum von Mises stress, and the restoration of shoulder joint function in the early postoperative period were 
studied. 
Results. The results of computer modeling using the finite element method showed that the von Mises stress distribution 
was smaller in the humerus model fixed by the new device than in the model fixed by the standard plate. In the humerus 
model with the standard plate, the displacement of bone fragments was greater. The patient who underwent surgery had 
good recovery of the shoulder joint function, with a Constant Murley (Score) score of 85%. 
Conclusion. Osteosynthesis of the proximal humerus fracture by the new device increases fracture stability, prevents 
secondary displacement of bone fragments and promotes early restoration of movement in the shoulder joint.