Chondral (Articular Cartilage) Defects
Articular or hyaline cartilage is the tissue lining the surface of the two bones in the knee joint. Cartilage helps the bones move smoothly against each other and can withstand the weight of the body during activities such as running and jumping. The articular cartilage does not have a direct blood supply, so it has less capacity to repair itself. Once the cartilage is torn, it cannot heal easily, which can lead to degeneration of the articular surface and to the development of osteoarthritis.
The damage in the articular cartilage can affect people of all ages. It can be damaged by trauma such as accidents, mechanical injury, such as a fall, or from degenerative joint disease (osteoarthritis), occurring in older people.
Patients with articular cartilage damage experience symptoms such as joint pain, swelling, stiffness and a decrease in range of motion of the knee. Damaged cartilage needs to be replaced with healthy cartilage by a surgical procedure called cartilage replacement. It is usually performed to treat patients with small areas of cartilage damage, usually caused by sports or traumatic injuries. It is not indicated for those who have advanced arthritis of knee.
Cartilage replacement helps relieve pain, restore normal function, and can delay or prevent the onset of arthritis. The goal of cartilage replacement procedures is to stimulate the growth of new hyaline cartilage. Various arthroscopic procedures involved in cartilage replacement include:
Microfracture: In this method, numerous holes are created in the injured joint surface using a sharp tool. This procedure stimulates the healing response by creating new blood supply. Blood supply results in the growth of new cartilage.
Drilling: In this method, a drilling instrument is used to create holes in the injured joint surface. The drilling creates blood supply and stimulates the growth of new cartilage. Although the method is similar to microfracture, it is less precise and the heat produced during drilling may damage other tissues.
Abrasion arthroplasty: A high-speed metal-like object is used to remove the damaged cartilage. This procedure is performed using an arthroscope.
Osteochondral autograft transplantation: Healthy cartilage tissue (graft) is taken from the bone that bears less weight and is transferred to the injured joint. This method is used for smaller cartilage defects.
Osteochondral allograft transplantation: A cartilage tissue (graft) is taken from a donor and transplanted to the site of the injury. The allograft technique is recommended if larger part of cartilage is damaged.
Autologous chondrocyte implantation: In this method, a piece of healthy cartilage from another site is removed using an arthroscopic technique and is cultured in the laboratory. Cultured cells form a larger patch, which is implanted in the damaged region by open surgery.
Following the surgery, rehabilitation procedures are advised to necessitate healing and to restore normal functioning of the joint.