In Silico Optimization of Femoral Fixator Position and Configuration by Parametric CAD Model.

Nikola Korunovic,Dragan Marinkovic,Milorad Mitkovic,Manfred Zehn,Miroslav Trajanovic,Saverio Affatato

doi:10.3390/ma12142326

Abstract

Structural analysis, based on the finite element method, and structural optimization, can help surgery planning or decrease the probability of fixator failure during bone healing. Structural optimization implies the creation of many finite element model instances, usually built using a computer-aided design (CAD) model of the bone-fixator assembly. The three most important features of such CAD models are: parameterization, robustness and bidirectional associativity with finite elements (FE) models. Their significance increases with the increase in the complexity of the modeled fixator. The aim of this study was to define an automated procedure for the configuration and placement of fixators used in the treatment of long bone fractures. Automated and robust positioning of the selfdynamisable internal fixator on the femur was achieved and sensitivity analysis of fixator stress on the change of major design parameters was performed. The application of the proposed methodology is considered to be beneficial in the preparation of CAD models for automated structural optimization procedures used in long bone fixation.

Highlights

Internal fixation based on biological, rather than mechanical priorities represents a well-established approach for treating long bone fractures, especially in the proximal femur [1]
The robustness of the computer-aided design (CAD) model of the femur–selfdynamisable internal and fixator (SIF) assembly was checked through the creation
The robustness of the CAD model of the femur–SIF assembly was checked through the creation of 16 The model instances

Summary

Introduction

Internal fixation based on biological, rather than mechanical priorities (biological internal fixation) represents a well-established approach for treating long bone fractures, especially in the proximal femur [1]. It allows, and even requires, that fractured segments remain mutually mobile [2]. Even requires, that fractured segments remain mutually mobile [2] While such mobility is often beneficial for the formation of a callus, it results in substantial loading of the applied fixation device, which may cause stability, strength, or durability related issues [3,4,5]. Parametric studies or optimization procedures have been employed to find the optimal configuration and position of an existing fixation device [13,14,15,16,17] or to optimize the shape and dimensions of a new one (e.g. [18])

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