WHAT IS OSTEOCHONDRAL ALLOGRAFT TRANSPLANTATION?
Osteochondral allograft transplantation is a useful technique to repair symptomatic articular cartilage defects with boney involvement or following a failed cartilage repair procedure (i.e., microfracture). An osteochondral allograft is a piece of fresh tissue containing bone and cartilage that is taken from a deceased donor. The allograft is used to replace damage cartilage that lines the ends of bones in the knee joint. X-rays with radiographic markers are needed to shape and precisely fit the allograft to the defect in the damaged knee joint. The x-rays are sent to a commercial procurement company that will find a suitable match. After screening the tissue for absence of disease, the fresh tissue will be available for transplantation.
Fresh tissue is preferable as cartilage viability is associated with a better long-term result. When the tissue becomes available you will be telephoned and you will need to come in within one week of the tissue being available. It may take as quick as two weeks or as long as three to six months before the appropriate match is available. Tissue typing is not required as in other organ transplantation with a blood supply, such as kidney, heart, or lung. Rejection of bone and cartilage is very rare and usually manifests as persistent swelling and a nonunion of the bone to bone junction.
WHAT WILL HAPPEN DURING MY SURGERY?
The implantation of osteochondral allograft is typically performed through an open incision, under general or spinal anesthesia. In surgery, the size of the defect is measured. A portion of the cartilage and underlying bone is then removed. The fresh allograft is shaped to match the size of the prepared defect. The allograft is then gently press-fit into the defect. Occasionally, further stabilization is needed using a screw/pin. A drain will be left inside the joint overnight to remove any postoperative bleeding from the donor site. The drain is either taken out in the hospital the following morning or the office. The procedure takes approximately 60 minutes to perform.