MATHEMATICAL MODELING OF THE STRESS-STRAIN STATE OF THE “BONE-IMPLANT” SYSTEM DURING THE OSTEOSYNTHESIS WITH A PHILOS WITH POLYLACTIC ACID IMPLANTS

Abstract

The aim: To study was to use mathematical modeling in assessing the stress-strain state of the bone-implant system during plate osteosynthesis with a PHILOS plate of a proximal humerus fracture with polylactic acid implants. Materials and methods: Two bone-implant systems with a three-fragment humerus fracture according to the Neer classification (type 11-C1 according to the AO / ASIF classification) were selected for the study, one of which was with additional reinforcement of the head fragment with two polylactic acid implants (PLA – polylactide Ingeo™ Biopolymer 4032D). Sawbones (Europe AB, Malmö, Sweden) built the humeral model on 3D scanning of the composite model № 3404 of the left humerus. Results: A comparative analysis of the obtained results of mathematical modeling of the stress-strain state of the bone-implant systems showed that with given constraints (hand abduction to 90°), the use of two polylactic acid implants can reduce the stress in the plate and screws, respectively, by 11% and 6% . Conclusions: The use of polylactic acid implants during osteosynthesis of three- and four-fragment fractures of the proximal humerus, especially in the case of osteoporosis, allows providing for the reinforcement of metal structures and supporting of the articular surface without deterioration of fixation rigidity.