Why does articular cartilage depend largely on synovial fluid for nourishment?

Articular cartilage is largely dependent on synovial fluid for nourishment primarily because it is an avascular tissue, meaning it lacks its own blood vessels to provide a direct supply of nutrients.1

Furthermore, the layer of cartilage nearest to the bone is impregnated with calcium salts, which acts as a physical barrier that prevents the passage of oxygen and nutrients from the bone into the cartilage. Consequently, the cartilage must rely on the synovial fluid, which acts as a blood plasma dialyzate, to deliver essential substances. This fluid is distributed across the surface of the cartilage through the natural movements of the joint, allowing nutrients to slowly diffuse into the interior of the cartilage matrix to support the metabolic needs of its cells, known as chondrocytes.2341