Construction and analysis of finite element model of defected articular cartilage

Study on the poroelastic behaviors of the defected osteochondral unit

Osteoarthritis has become a major disease threatening human health. The mechanism of injury under fluid involvement can be studied by finite element method. However, most models only model the articular cartilage to study the subchondral bone structure, which is too simplistic. In this study, a complete osteochondral unit was modeled and provided with a poroelastic material, and as osteoarthritis develops and the size, thickness, and shape of the osteochondral unit defect varies, the fluid flow behavior is altered, which may have functional consequences that feed back into the progression of the injury. The results of the study showed that interstitial fluid pressure and velocity decreased in defective osteochondral units. This trend was exacerbated as the size and thickness of the defect in the osteochondral unit increased. When the defect reached the trabeculae, pressure around the cartilage defect in the osteochondral unit was greatest, flow velocity in the subchondral cortical bone was greatest, and pressure and flow velocity around the trabecular defect were lowest. As osteoarthritis develops, the osteochondral unit becomes more permeable, and the pressure of the interstitial fluid decreases while the flow rate increases, resulting in severe nutrient loss. This may be the fluid flow mechanism behind osteochondral defects and osteoarthritis.

Magnetic Resonance Imaging-based biomechanical simulation of cartilage: A systematic review

MRI-based mathematical and computational modeling studies can contribute to a better understanding of the mechanisms governing cartilage's mechanical performance and cartilage disease. In addition, distinct modeling of cartilage is needed to optimize artificial cartilage production. These studies have opened up the prospect of further deepening our understanding of cartilage function. Furthermore, these studies reveal the initiation of an engineering-level approach to how cartilage disease affects material properties and cartilage function. Aimed at researchers in the field of MRI-based cartilage simulation, research articles pertinent to MRI-based cartilage modeling were identified, reviewed, and summarized systematically. Various MRI applications for cartilage modeling are highlighted, and the limitations of different constitutive models used are addressed. In addition, the clinical application of simulations and studied diseases are discussed. The paper's quality, based on the developed questionnaire, was assessed, and out of 79 reviewed papers, 34 papers were determined as high-quality. Due to the lack of the best constitutive models for various clinical conditions, researchers may consider the effect of constitutive material models on the cartilage disease simulation. In the future, research groups may incorporate various aspects of machine learning into constitutive models and MRI data extraction to further refine the study methodology. Moreover, researchers should strive for further reproducibility and rigorous model validation and verification, such as gait analysis.

Enhanced In Vitro and In Vivo Efficacy of Alginate/Silk Protein/Hyaluronic Acid with Polypeptide Microsphere Delivery for Tissue Regeneration of Articular Cartilage

Alginate/Silk fibroin/hyaluronic acid (ALG/SF/HA) nanocomposites were synthesised using blending, inter-linking, and lyophilization methods. We investigated the physicochemical properties of the resulting nanocomposites, including their water retention, weight loss, porosity and cytocompatibility. The optimum ratios of the ALG/SF/HA scaffolding were 3:6.5:0.5. Nanocomposites with optimum ratios were then prepared by integrating pilose antler polypeptides (PAPS) to poly(lactic-co-glycolic acid) (PLGA) microspheres, and the performance was investigated. PAPS-ALG/SF/HA nanocomposites exhibited desirable adhesions and proliferations. Rabbit cartilage deficiencies was developed by the animal model. The cartilage repair effects deficiencies were detected and analyzed between PAPS-SF/ALG/ALG/SF/HA, and control activity classes. The deficiencies were virtually fully remedied after 13 weeks in the presence of PAPS-ALG/SF/HA class, suggesting that the PAPS-ALG/SF/HA nanocomposites had a positive effects on joint cartilage repair.