A Reproducible Method for Simulating Malunited Fifth Metacarpals: Applications in Finite Element Analysis and Biomechanical Research

Understanding the relationship between deformity angles and the mechanical properties of metacarpals is crucial for studying refractures in malunited fifth metacarpals. However, the lack of specimens with diverse deformity angles and positions presents a significant challenge. Finite element analysis (FEA) offers a non-invasive approach but requires a variety of metacarpal models. This study aims to propose a reproducible method to simulate malunited fifth metacarpals from normal fifth metacarpals, providing models for FEA and biomechanical studies. A computational coordinate system was designed to guide the simulation process. The method includes three main steps: modeling healthy fifth metacarpals from CT data, constructing the metacarpal coordinate system, and simulating malunited metacarpals with different deformity angles and positions. This study designed a numerical experiment to compare the results of static analysis between the simulated malunited metacarpal generated using the proposed method and the real malunited metacarpal. The results showed that the simulated malunited model exhibited equivalent Von-Mises stress values and similar stress distributions to those of the real malunited metacarpal under the same loading conditions. The study also presents an example of the application of the proposed methods. The proposed method provides a reproducible and efficient approach for generating diverse malunited fifth metacarpal models. It offers valuable tools for FEA and biomechanical research, enabling further studies on deformity-related mechanical behavior and refracture phenomena.