What is the primary cause of osteoarthritis?

The primary cause of osteoarthritis is indeed the degeneration of articular cartilage from proteoglycan loss. Osteoarthritis is characterized by the gradual wear and tear of the cartilage that cushions the ends of bones in the joints. This degeneration leads to a reduction in the overall quality and quantity of cartilage, resulting in pain, stiffness, and reduced mobility.

In healthy cartilage, proteoglycans help retain water and provide structural support. As these molecules break down, the cartilage loses its ability to function effectively, leading to a cascade of changes in the joint, including bone remodeling, the formation of osteophytes (bone spurs), and inflammation. While some inflammation may occur as a secondary reaction to the degeneration, it is not the primary cause of osteoarthritis. The disease is primarily driven by the mechanical and biochemical forces that lead to cartilage breakdown over time, often influenced by age, obesity, and previous joint injuries.