Browsing by Author "Rodrigues, Mafalda Filipe de Paiva"
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- Bioactive 3D printed interference screws for orthopedic implant fixationPublication . Rodrigues, Mafalda Filipe de Paiva; Costa, João Pedro Bebiano; Oliveira, Ana Leite de Almeida Monteiro deMusculoskeletal injury (MSI) corresponds to the disruption of muscles, tendons or ligaments. The knee is one of the most affected areas, with the meniscus and ligaments being very susceptible to injury due to their role in stabilizing the knee joint. A variety of treatments are available for these injuries, ranging from more conservative approaches to surgical interventions, such as ligament reconstruction, meniscectomy, repair or reconstruction of the meniscus. One of the primary challenges associated with these surgical procedures is ensuring adequate tissue fixation, which is typically achieved through the use of sutures, staples or interference screws. Although there are a variety of interference screws currently on the market, including metal and biodegradable models, there are still limitations regarding their rapid fixation and long-term effectiveness. The aim of this thesis was to address these limitations by developing a bioactive interference screw, combining three-dimensional (3D) printing technology and supercritical carbon dioxide (scCO2) technology, as a porogen and impregnation agent. In this study, polylactic acid (PLA) was used as the base material for printing and the impact of infill density during 3D printing, the effect of batch pressure on the foaming process and, finally, the effect of impregnating an exopolysaccharide (EPS) on the biological behavior of the screws were explored. A reduction in infill density, coupled with a decrease in batch pressure, resulted in a higher expansion ratio, leading to augmented pore density and augmented internal microporosity, characterized by the presence of larger pores. Furthermore, the impregnation process, whereby the screw is subjected to a scCO2 environment once more, induced surface roughness and altered the microporosity induced by foaming, thereby rendering the screw more resistant. All the screws developed were found to be biocompatible through cytotoxicity tests. However, further tests will be required to gain a deeper understanding of the screw's overall performance, both mechanically and biologically. The findings demonstrate the potential of combining these innovative technologies to produce interference screws with advanced properties. The results obtained in this work could open up new possibilities for developing this type of medical device in a way that is reproducible, effective and provides bioactive properties.