In the present study, the effects of human physiological activity levels on the fatigue life of a porous magnesium scaffold have been investigated. First, the dynamic immersion and biomechanical testing are carried out on a porous magnesium scaffold to simulate the physiological conditions. Then, a numerical data analysis and computer simulations predict the implant failure values. A 3D CAD bone scaffold model was used to predict the implant fatigue, based on the micro-tomographic images. This study uses a simulation of solid mechanics and fatigue, based on daily physiological activities, which include walking, running, and climbing stairs, with strains reaching 1000–3500 µm/mm. The porous magnesium scaffold with a porosity of 41% was put through immersion tests for 24, 48, and 72 h in a typical simulated body fluid. Longer immersion times resulted in increased fatigue, with cycles of failure (Nf) observed to decrease from 4.508 × 1022 to 2.286 × 1011 (1.9 × 1011 fold decrease) after 72 hours of immersion with a loading rate of 1000 µm/mm. Activities played an essential role in the rate of implant fatigue, such as demonstrated by the 1.1 × 105 fold increase in the Nf of walking versus stair climbing at 7.603 × 1011 versus 6.858 × 105, respectively. The dynamic immersion tests could establish data on activity levels when an implant fails over time. This information could provide a basis for more robust future implant designs.

The subchondral bone layer has an important role in supporting the articular cartilage under mechanical loads. Therefore, subchondral bone can affect cartilage damage, in this case osteoarthritis. Many studies have addressed osteoarthritis, but few studies have focused on the influence of subchondral bone morphology on the development of osteoarthritis. The purpose of this narrative review is to examine the relationship between subchondral bone morphology and the development of osteoarthritis by looking at the morphological differences between normal and osteoarthritis patients. The method used in the screening process for reputable journals, the author uses End-Note software. The keywords used are cartilage, osteoarthritis, subchondral bone, and morphology. Article search focused on pubmed database with several criteria. Then after getting the article, the data will be extracted into a table for further narrative review process. From the data obtained, it can be concluded that the morphological value in osteoarthritis patients is greater than normal patients, and patients suffering from osteoarthritis are infected more often in elderly patients. Other factors that can affect osteoarthritis are weight, height, and body mass index.

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The purpose of this study was to determine fatigue in a porous magnesium bone scaffold. It applies finite element simulation in assessing bone scaffolding's fatigue behaviour with variations in axial loading based on physiological activities in humans. By applying the boundary conditions to the solid mechanics model and fatigue simulation, it subjects each specimen to a different loading of 1000 -3500 με, which gives the bone scaffold displacement variations. The simulation results of fatigue life for the porosity of 30%, 41%, and 55% show that the greater the loading, the lower the number of failure cycles on the porous magnesium bone scaffold. For a porosity of 30% with a load of 1000 -3500 με, it produces the number of failure cycles from 3.99x10 22 -3.61 x10 16 .

This paper proposes a modeling approach for biodegradation of implant-bone scaffolds. A Computer simulation was performed to determine the wall shear stress (WSS) and permeability of simulated body fluid (SBF) with a constant flow rate of 0.025 ml/min. In this study, four morphological samples were used to immersion time from 0 to 72 hours. Each specimen was given a different bone strain (1000-3500 μstrain) which created a variation of displacement in the bone scaffold. The method used in the simulation was the fluid-structure interaction (FSI). The pressure drop through the specimen decreases linearly, the permeability increases as the porosity increases, and the mean wall shear stress decreases due to the length of the immersion time. It was obtained that the permeability values of the implant-bone scaffold increases from 7.79×10-10 m2 to 1.09×10-9 m2 and the mean shear stress values decrease from 2.86×10-3 Pa to 1.38×10-3 Pa.