Clinical analysis of 16 patients with Clostridium butyricum isolated from blood cultures: A 10-year single-center case series and review of published cases.

Knee cartilage injury is a common condition in sports medicine and orthopedics. The self-repair capacity of injured articular cartilage is very limited, owing to its avascular and aneural nature, as well as the poor proliferative ability of chondrocytes. Consequently, without timely and standardized intervention, such injuries can easily progress to osteoarthritis, resulting in a substantial social and healthcare burden. Notably, recent years have witnessed accumulating evidence confirming the critical role of gas molecules and related regulatory factors in cartilage repair, establishing them as a key research hotspot in this field. Substantial progress has been made in understanding the basic mechanisms of knee cartilage injury and repair. Endogenous gasotransmitters, such as nitric oxide (NO), oxygen (O), hydrogen (H), and hydrogen sulfide (HS), have been shown to regulate cartilage repair via multiple signaling pathways. Among these, H exerts chondroprotective effects by acting as a selective antioxidant, suppressing the inflammatory microenvironment, and restoring mitochondrial function in chondrocytes. HS mitigates cartilage degeneration by downregulating matrix metalloproteinases (MMPs) and thereby reducing type II collagen degradation. The development of targeted delivery systems for these molecules has accordingly become a prominent research direction. At the level of related factors, reactive oxygen species (ROS) have gained increasing recognition for their dual roles in cartilage injury and repair. Pro-inflammatory cytokines such as interleukin-1β (IL-1β) and tumor necrosis factor-alpha (TNF-α) are established drivers of cartilage matrix degradation and chondrocyte apoptosis. Conversely, transforming growth factor-beta (TGF-β), bone morphogenetic proteins (BMPs), and growth differentiation factor 15 (GDF-15) promote chondrocyte proliferation, differentiation, and matrix synthesis, thereby representing key targets for cartilage regeneration. In parallel, bibliometric and visualization analysis methods have been widely used in medical research to identify emerging trends. Both approaches facilitate quantitative, panoramic assessments of research landscapes, scholarly collaboration networks, and the evolution of thematic foci. Significant gaps remain in current research on gas molecules and related factors in knee cartilage injury repair. Specifically, differences in research focus among various molecules, the extent of attention to cross-regulatory networks, and the status of translational research bottlenecks have not been sufficiently quantified or analyzed. It should be noted that the literature identified in this study predominantly addresses the degenerative osteoarthritis process, whereas research specifically focused on acute traumatic cartilage injury remains comparatively scarce. To address these issues, this study uses bibliometric and visualization methods to systematically map the global research status, evolving hotspots, and knowledge structure in this field. By identifying core authors, key literature, research frontiers, and emerging topics, this study aims to provide researchers with a clear understanding of the landscape of the field, outline promising future directions, and establish a theoretical foundation for developing gas signaling–based cartilage repair strategies. However, bibliometric evidence for H and HS remains limited, and this study focuses on molecules with sufficient literature volume for clustering analysis.