Cartilage Repair for the Knee
Cartilage is a type of tough tissue that is located in regions of the body that engage in continuous movements to prevent wear and tear. It is synthesized by the cells referred to as chondrocytes. Articular cartilage is the tissue that lines the surfaces of a joint. The cartilage provides a smooth finish to the bone ends and helps in reducing friction during movement.
Cartilage is not as rigid as bone and posses a degree of flexibility. It does not contain blood vessels and receives nutrients via diffusion from surrounding bones. It also has no nerve endings and hence no pain is appreciated once it is damaged.
Despite its tough composure, cartilage is prone to several disease processes. In osteoarthritis, the cartilage becomes worn out as a result of wear and tear. This exposes the bone ends to each other resulting in increased friction and pain during movement. Cartilage is not spared by trauma and suffers damage from car accidents, sports injuries and more. when cartilage is injured, the body typically cannot repair and restore due to its limited metabolism.
Once cartilage is damaged, it is almost impossible for it to repair because of its avascular nature. Because it cannot replace cartilage tissue, the body results in depositing fibrous tissue into the defect. The fibrous tissue is not able to deliver the same function as the cartilage and this causes joint dysfunction.
Types of cartilage repair for the knees
Autologous chondrocyte transfer is a technique that utilizes the chondrocytes from the patient and uses them to regenerate cartilage and cover a defect elsewhere. The chondrocyte cells are harvested from a non weight bearing area of the knee joint through arthroscopy. The cells are then grown in a laboratory for a period of six weeks. One the growth is complete; the cells are transplanted into the damaged area by use of arthrotomy. The cells are injected into that area that has a defect and covered with periosteum. There is minimal risk of rejection because the procedure utilizes cells from the patient themselves. This procedure is recommended for young patients with defects of more than 2cm in the cartilage.
In cell based cartilage resurfacing, chondrocyte cells are harvested from a non weight bearing area of the knee joint. The cells are then grown in a laboratory and then transferred to a scaffold where they continue growing. Once an adequate piece of cartilage has grown, it is implanted back into the knee and fixed into position by use of a bioadhesive. The cartilage eventually matures and integrates with the existing cartilage.