OSTEOCHONDRAL AUTOGRAFT
Osteochondral autograft (OATS) is a technique that requires that the surgeon transplant sections of bone and cartilage. First, the damaged section of bone and cartilage is removed from the joint. Then a new healthy dowel of bone with its cartilage covering is removed from the same joint and transplanted or grafted into the hole left from removing the old damaged bone and cartilage. The healthy bone and cartilage are taken from areas of low stress in the joint so as to prevent weakening the joint. Depending on the severity and overall size of the damage multiple plugs or dowels may be required to adequately repair the joint. A similar treatment, known as mosaicplasty, is described in the next paragraph.
GRAFTING
There are three methods of grafting cartilage defects:
1) Periosteal grafting
Periosteal grafts are harvested from the perichondrial tissue and grafted to the articular cartilage defect. Given low long-term success rates, perichondrial grafting alone has not been clinically accepted as a particularly excellent therapy.
2) Osteochondral grafting (mosaicplasty)
Mosaicplasty, a form of chondral grafting, is a therapy designed to replace cartilage on the surface of the knee joint that has been damaged by trauma or arthritis by implanting osteochondral plugs. The implants can be autogenic (autologous) or allogenic.
3) Articular cartilage stem cell paste grafting
Paste grafting involves replacing damaged cartilage with autologous cartilage and cancellous bone from the intercondylar notch in the center of the knee that is first morselized into a paste (typically with hydroxyapatite) to better fill the defect and more successfully promote chondrocyte activity and cartilage formation.
These procedures are often performed arthroscopically.
