Why does articular cartilage heal slowly after it is injured?

Articular cartilage heals slowly after an injury primarily because it is avascular, meaning it lacks its own blood vessels to supply the nutrients and cells necessary for efficient repair.12

Unlike many other tissues in the body, articular cartilage relies on indirect nourishment from synovial fluid, which is distributed across the cartilage surface through joint movement. Because the tissue is devoid of both blood vessels and nerves, the metabolic processes required for regeneration are limited. Furthermore, the repair capacity of cartilage is constrained by a relatively low abundance of cells (chondrocytes) capable of producing the necessary matrix to mend damaged areas. Consequently, when articular cartilage is injured, the body struggles to regenerate the tissue effectively, often leading to an imbalance between cartilage breakdown and repair that can contribute to the development of osteoarthritis.1324