Abstract The gut microbiota functions as a critical regulator of bone development and homeostasis through a proposed ‘three-layer defense system’: basal homeostatic maintenance, danger sensing, and active repair. Microbial metabolites such as short-chain fatty acids, tryptophan derivatives, and vitamin K modulate bone metabolism via GPCR signaling, epigenetic regulation, and immune modulation, establishing a foundation for skeletal health. Endocrine axes – including estrogen, GH/IGF-1, and PTH – interact with the gut microbiota to influence bone remodeling, with dysbiosis contributing to inflammatory amplification and osteoclast activation via RANKL/NF-κB pathways. The third-layer defense involves targeted repair through probiotics and bacterial extracellular vesicles, which restore immune homeostasis, enhance osteogenesis, and suppress bone resorption. Therapeutic strategies targeting this multi-layer system – including probiotic interventions, fecal microbiota transplantation, and bioactive compound supplementation – offer promising avenues for personalized prevention and treatment of metabolic bone diseases.
Abstract Venous thromboembolism prophylaxis after total joint arthroplasty remains heterogeneous, particularly regarding the role of aspirin within modern fast-track pathways. Although aspirin is widely used in North American arthroplasty practice, European guidelines remain more conservative and often provide limited or non-operational recommendations for its use after total hip and knee arthroplasty. Contemporary evidence supports aspirin as a viable prophylactic option in selected patients, with potential advantages related to its safety profile, cost, ease of administration and reduced treatment burden. The clinical role of aspirin should be interpreted within a risk-stratified framework that accounts for thromboembolic risk, bleeding risk, surgical complexity, early mobilization and duration of prophylaxis. Available evidence, including recent randomized data, supports aspirin-based prophylaxis in appropriately selected patients, both as part of sequential strategies and, increasingly, as monotherapy within contemporary fast-track pathways. This scoping review synthesizes current guideline-level evidence and contemporary clinical data to clarify practical considerations for agent selection, dosing, duration and aspirin-based prophylaxis after total joint arthroplasty.
