Біомеханічне обґрунтування вибору засобу фіксації кісткових фрагментів при проксимальній остеотомії першої плеснової кістки

Abstract

One of the most common pathologies that occurs in static deformities of the anterior joint of the foot in the foot is valgus deformity of the first toe. Distal or diaphyseal osteotomies are used for mild degrees, and proximal osteotomies for severe ones. Spikes, screws or plates with angular stability are most often used to fix bone fragments. Purpose - with the help of biomechanical studies, to study the stress-deformed state of the foot model with different options for osteosynthesis of the first metatarsal bone after the proximal osteotomy. Materials and methods. Mathematical modeling of osteosynthesis of the first metatarsal bone during correction of valgus deformity of the first toe using proximal osteotomy was carried out. Three variants of osteosynthesis were modeled: Kirschner pins, screws, and a bone plate. Results. During osteosynthesis with spikes, maximum stresses of 2.1 MPa occur in distal fragment. In the proximal fragment, the stresses are twice as low - 1.2 MPa. The tension in the resection zone is 0.1 MPa. During osteosynthesis with screws, the stresses in the proximal and distal fragments of the bone are almost the same, and are 0.9 MPa and 0.8 MPa, respectively. The tension in the osteotomy zone is 0.1 MPa. Osteosynthesis with a bone plate provides a low level of stresses in the osteotomy zone - 0.1 MPa, as well as an even distribution of stresses between the proximal and distal fragments of the metatarsal bone - 0.8 MPa and 0.7 MPa, respectively. During osteosynthesis with spikes and screws, the relative deformation of the bone regenerate does not exceed 0.13%. During osteosynthesis with a bone plate, this figure reaches 0.5%. Conclusions. For osteosynthesis of bone fragments during proximal osteotomy of the first metatarsal bone in order to eliminate valgus deformity of the first toe, spikes, screws and a bone plate can be used. All investigated types of osteosynthesis provide a low level of stress in the osteotomy zone of the first metatarsal bone, but, according to the criterion of stress values in the proximal and distal fragments of the bone, osteosynthesis with spikes showed the worst result, and osteosynthesis with a bone plate showed the best. The research was carried out in accordance with the principles of the Helsinki Declaration. The study protocol was approved by the Local Ethics Committee of the participating institution. The informed consent of the patient was obtained for conducting the studies. No conflict of interests was declared by the authors.