A novel etiological approach for the development of knee osteoarthritis in sedentary adults

• Published in: Medical hypotheses 2024-04, Vol.185, p.111291, Article 111291
• Main Author: del Río, Eloy
• Format: Article
• Language: English
• Subjects: Bipedal evolution; Cartilage thickness; Knee osteoarthritis; Physical activity; Sedentary behavior; Unstirred diffusion barrier
• ISSN: 0306-9877; 1532-2777
• DOI: 10.1016/j.mehy.2024.111291

•This study explores the pathogenesis of knee OA in developed countries.•Increased knee OA is linked to cartilage thickness and a sedentary lifestyle.•Daily physical activity may prevent early knee OA in inactive individuals. Knee osteoarthritis, a common degenerative disease that causes a huge socioeconomic burden, is characterized by gradual deterioration of the articular cartilage, often leading to pain, stiffness, and impaired joint function. Addressing a significant public health concern, this study suggests that the combined effect of characteristic knee cartilage thickness—presumably a consequence of bipedal evolution—and the modern sedentary lifestyle has given rise to a distinctive osteoarthritis endotype referred to as ‘stagnant cartilage syndrome’. This bombastic term highlights the challenges associated with thick cartilage: the physiological demands for its maintenance. The hypothesis posits that physical inactivity contributes to knee osteoarthritis development by promoting a stagnant diffusion barrier at the synovial fluid-cartilage interface. Such a surface phenomenon may lead to a limiting depth of cartilage, hindering nutrient supply and leading to waste accumulation, disruption of cell homeostasis, and progressive tissue degradation. If validated, this approach could enhance our understanding of knee osteoarthritis pathogenesis, emphasizing the need to address the relationship between cartilage thickness and sedentary behavior in developing effective evidence-based preventive strategies.