Arthrodesis of the equine proximal interphalangeal joint: biomechanical and finite elements study of the occurrence of stress riser in different forms of proximal screw application in locking compression plate

• Grant number: 22/13143-3
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate (Direct)
• Start date: April 01, 2023
• End date: September 30, 2023
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Clinics and Surgery
• Principal Investigator: André Luis do Valle de Zoppa
• Grantee: Anderson Fernando de Souza
• Supervisor: Jan Michael Kummerle
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: University of Zurich (UZH), Switzerland
• Associated to the scholarship: 21/07105-9 - Arthrodesis of the equine proximal interphalangeal joint: biomechanical and finite elements study of the occurrence of stress riser in different forms of proximal screw application in locking compression plate, BP.DD

Abstract

This project aims to describe the mechanical characteristics, stress distribution and occurrence of failures in AIP, using 3-hole 4.5mm LCP, in combination with two 5.5mm transarticular cortical screws, with different forms of application of the proximal screw. The mechanical testing of axial loading will be performed on 20 cadaveric specimens, divided into four groups according to the type of proximal screw applied to the plate: GCU - cortical screw unicortical; GCB - cortical screw bicortical; GLU - locking screw unicortical; and GLB - locking screw bicortical. Stiffness, deformation and force will be measured at the apparent elastic limits and maximum strength. Electrical resistance extensometry will be used to measure microstrain in the plate and in the proximal phalanx. CBCT scans will be performed before and after the testing to evaluate the failures that have occurred, as well as the identification of plastic deformations in the implants. The stress distribution and the occurrence of stress riser will be analyzed by the finite element method, simulating the conditions of the mechanical testing and ankylosis, combined with the presence or absence of implants. Extensometry data will be used for model validation. The results of this work may help to choose the most efficient type of screw and anchor to be used in the proximal orifice of the LCP in the AIP. Thus, generating a construction with greater stability, which in practice translates into greater comfort and less convalescence for the patient. (AU)