Stopping and stripping torques of three types of screws applied in a model of lateral condylar fracture in the third metacarpal bone of horses: Ex vivo study

• Grant number: 24/12339-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2024
• End date: September 30, 2025
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Clinics and Surgery
• Principal Investigator: André Luis do Valle de Zoppa
• Grantee: Beatriz Martins de Ávila
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The use of fully implanted screws may offer benefits for the fixation of lateral condylar fractures of the third metacarpal in horses compared to traditional cortical screws. For the fixation of these different types of screws, the surgeon manually applies a torque force, determining subjectively and individually the necessary intensity, which may sometimes be insufficient or even lead to screw head failure or implant-bone interface failure. The objective of this project is to evaluate the insertion and rupture/stripping torques, as well as the associated failures, between the conventional 4.5mm stainless steel cortical screws, 6.5mm double-thread screws, and 6.0mm conical screws in titanium alloy, applied in an equine ex vivo model of lateral condylar fracture in the third metacarpal. An osteotomy will be performed to simulate a complete lateral condylar fracture without fragment displacement in 18 third metacarpals from adult equine cadavers, divided into three groups based on the type of screw: PP, group with conventional AO 4.5 mm stainless steel cortical screw; PD, group with 6.5mm double-thread cannulated screw in titanium alloy; and PC, group with 6.0mm conical cannulated screw in titanium alloy. The peak insertion torque and the rupture and stripping torque will be measured with a digital torque meter. The data from this study will aid in understanding the mechanical capacity of new implant options for application in condylar fractures, thus improving techniques and outcomes in clinical cases.