Publication: Influences of screw designs on bone screw fixation, pull-out strength and local deformation of cortical bone
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Date
2024-07-12
Authors
Nurul Nabila binti Abu Bakar
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Abstract
The design of orthopaedic screw plays an important role in ensuring the proper fixation and pull-out testing which reducing complication during bone surgeries. Bone screws are frequency used in orthopaedic screw to maintain the position of broken bones through the compression force exerted by the screws and facilitating bone fracture healing. However, research indicates that failure of the bone screw may result in fracture and loosening, which can lead to loss of fixation and painful bone. Several studies have recommended several remedies, including modifying the substance of the screw and adjusting the screw's depth of insertion. By employing numerical simulation through the Ansys Workbench platform, the impact of various geometries on fixation strength and local deformation is evaluated. The insertion and pull-out tests were performed using polyethylene foam blocks with a density of 0.32 g/𝑐𝑚3 as substitutes for bone specimens, ensuring consistent testing conditions and preventing deformation or breakage. Furthermore, the stainless steel was chosen for screw material properties. This study has three main aims which, first, to numerically evaluate how different screw designs affect fixation strength within cortical bone. Secondly, to determine the variations in pull-out strength due to screw design. Thirdly, to analyse the local deformation of cortical bone caused by different screw geometries under pull-out forces. The study's findings request to provide useful insights for optimizing screw designs, ultimately improving the performance and dependability of orthopaedic implants. Additionally, the stress-strain distribution was concentrated at the screw-bone contact zone during insertion, improving fixation strength despite variations in geometric features. These findings underscore the importance of optimizing screw design parameters to maximize fixation strength and improve the overall effectiveness of orthopaedic implants.