Cartilage replacement is a surgical procedure performed to replace the worn-out cartilage with new cartilage. 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 patients who have advanced arthritis of the knee. Articular or hyaline cartilage is the tissue that covers the bone surfaces and helps in smooth interaction between the bones in knee joint. It has less capacity to repair by itself because there is no direct blood supply to the cartilage.
Cartilage replacement helps relieve pain, restore normal function, and can delay or prevent the onset of arthritis. The goal of the cartilage replacement procedures is to repair and stimulate growth of new hyaline cartilage. Various arthroscopic procedures involved in cartilage replacement include:
- Microfracture: Microfracture involves creating numerous tiny holes in the injured joint surface using a special tool, called ‘awl'. The holes are made in the bone under the cartilage, called the subchondral bone. This creates new blood supply to the cartilage to stimulate the growth of the new cartilage.
- Drilling: This procedure is like microfracture where multiple holes are created in the injured joint area using a surgical drill or wires.
- Abrasion arthroplasty: This procedure is like drilling, but involves the use of high-speed burs to remove the damaged cartilage.
- Autologous chondrocyte implantation (ACI): This is a two-step procedure, where healthy cartilage cells are removed from a non-weight bearing joint, grown in the laboratory and then implanted in the cartilage defect during the second procedure. During this procedure, a patch is harvested from the periosteum, a layer of thick tissue that covers the bone, and is sewn over the defected area using fibrin glue. The new cartilage cells are then injected under the periosteum into the cartilage defect to allow the growth of new cartilage cells.
- Osteochondral autograft transplantation: In this procedure, plugs of cartilage are taken from the non-weight bearing areas of knee, from the same individual, and transferred to the damaged areas of the joint. This method is used to treat smaller cartilage defects since the graft, which is taken from the same individual, will be limited.
Osteochondral allograft transplantation: : In this procedure, healthy cartilage tissue or a graft is taken from a donor, from the bone bank and transplanted to the area of cartilage defect.
Following cartilage replacement your doctor may recommend physical therapy to help restore mobility to the affected joint.