Evolution of knee osteoarthritis biomechanics research, 2005–2025: bibliometric mapping and machine-learning-assisted topic modeling

Background Knee osteoarthritis (KOA) involves interactions among whole-joint loading, tissue mechanics, and cellular responses. This study mapped the structure and temporal evolution of KOA biomechanics research using bibliometric analysis and machine-learning-assisted topic modeling. Methods English-language articles and reviews published from 2005 to 2025 were retrieved from the Web of Science Core Collection and Scopus, merged, deduplicated, and screened. The final corpus comprised 3110 publications. Publication patterns, collaboration networks, citation structures, and keyword themes were evaluated, and non-negative matrix factorization was applied to bibliographic text to identify latent topics and their temporal distribution. Results Annual output increased from 37 publications in 2005 to 321 in 2025. The United States led in publication output and total citations, while the University of Melbourne was the most productive institution. Keyword analysis identified five major domains spanning mechanobiology, gait and neuromuscular control, conservative load-modifying interventions, alignment correction and reconstruction, and meniscal and ligament mechanics. The selected model comprised 19 topics. Gait and lower-limb kinematics had the largest overall share. The greatest increases in mean annual topic share from 2016-2020 to 2021-2025 involved stem cells and regenerative cartilage repair, chondrocyte mechanotransduction, and meniscal tears, extrusion, and root repair. Recent changes in topic share were strongly correlated between hard and normalized soft assignments (Spearman's ρ = 0.926). Conclusion Overall, publication output increased, and topic-share patterns indicated greater relative representation of mechanobiology, regenerative repair, meniscal preservation, and alignment correction, while gait and loading research remained prominent. These findings provide a descriptive map of the field's development and changing research priorities.