The results indicate that cultured autologous chondrocytes can be used to repair articular cartilage defects in the femorotibial joint, and show that this treatment restores the function of the joint by forming predominantly hyaline-like cartilage containing type II collagen. However, the mechanism of the repair process is unknown. The procedure enables patients to grow new hyaline cartilage in their knees. Hyaline cartilage is the tough, slippery tissue that cushions the ends of bones where they form a joint. It lets bones glide smoothly during joint motion, and distributes the force evenly during running, jumping, and other repetitive movements.
Hyaline cartilage consists of chondrocytes and extracellular matrix.
The matrix contains a variety of macromolecules, including type II collagen and proteoglycan. The structure of the matrix allows the cartilage to absorb shock and withstand shearing and compression forces. After a surgical procedure is completed, fibrocartilage rather than hyaline cartilage is most commonly produced. Fibrocartilage has limited ability to withstand shock and shearing forces. Currently, the procedure is limited to patients aged 55 or younger.