Design and rapid prototyping of orthopaedic device for lower limb fractures

Abstract

Bone fractures are a prevalent occurrence on a daily basis, posing significant challenges to healthcare systems in terms of hospital admissions, surgical procedures, and medication requirements. These fractures primarily result from either pathological conditions or highenergy trauma, including incidents such as car accidents, falls, and natural disasters. The treatment of bone fractures necessitates the use of bone fixation devices, which can be either internal or external, to provide stability to the injury, promote bone healing, and enable the patient to regain full functionality. The current designs of fixation devices, along with the materials utilised in their manufacturing, lead to fixators that are excessively heavy, lack comfort and lack of customisation to meet the unique requirements of individual patients. These concerns highlight the necessity of continued progress in the development of fixation devices to achieve improved and personalised medical treatments, with the aim of enhancing clinical outcomes and reducing costs. Therefore, the aim of this research project is to overcome the identified limitations by developing an innovative, customised, and optimised bone fixation system that is both costeffective and lightweight, while ensuring its structural integrity through the utilisation of topology optimisation, polymeric material and additive manufacturing. The bone fixation systems were successfully optimised, taking into consideration various loading conditions and mass reduction values. Fused deposition modelling additive manufacturing was employed to fabricate the optimised models. Subsequently, the bone fixation systems underwent numerical and mechanical evaluation and validation. The results indicate that an increase in mass reduction leads to higher stress and displacement, which can be attributed to material removal. Furthermore, it was observed that these optimised systems possess adequate mechanical characteristics, as evidenced by the IFM falling within the acceptable range and the stresses generated in the system remaining below the yield strength. This demonstrates the potential of utilising polymeric materials and topology optimisation in the development of bone fixation devices. This research presents a novel approach involving the use of polymeric materials and topology optimisation to create custom fixation devices tailored to individual patient anatomy. This is the first type of fixation that could represent a potential alternative to the existing conventional fixations, offering promising prospects.