What is a Knee Cartilage Transplant?
Hyaline (articular) cartilage has a limited capacity to regenerate and heal itself due to its lack of blood supply. The only way to truly fill a cartilage defect with normal cartilage is through a cartilage transplant procedure. A number of cartilage transplant procedures have been developed which involve either transplanting cartilage and bone from one part of the knee to another (osteochondral transplant) or implanting new cartilage cells into the cartilage defect (autologous chondrocyte implantation).
How Can Osteochondral Transplant Surgery Relieve Your Knee Pain?
Osteochondral transplant procedures are designed to treat full thickness cartilage defects. They are known by a variety of names, including mosaicplasty and OATS procedure – a proprietary name that stands Osteochondral Autograft Transfer System. Osteochondral transplant involves harvesting a cylinder or plug of bone and overlying cartilage from an area in the knee that does not require cartilage and transplanting it into the cartilage defect. One or, sometimes, multiple plugs are transplanted to fill the cartilage defect completely. Large cartilage defects can be treated with allograft (cadaver) osteochondral grafts.
The advantage of this procedure is that the cartilage defect is filled with normal hyaline cartilage. The typical patient considered for this procedure is a young, active individual with a isolated traumatic cartilage injury. This procedure is performed through a minimally invasive arthroscopic technique or an open technique depending on the size and location of the lesion. The postoperative rehabilitation involves a period of limited weight bearing with crutches (6 weeks) and the use of a continuous passive motion machine (CPM).
What Happens During An Autologous Chondrocyte Implantation?
This procedure was developed to fill the cartilage defect with more normal hyaline-like cartilage. It is sometimes referred to by its proprietary name – the Carticel procedure. It involves 2 separate operations. The first procedure is a short arthroscopic procedure where cartilage cells (chondrocytes) are harvested from a non-essential part of the knee. These cells are then grown (cultured) in a laboratory for 6-8 weeks. A second procedure is then performed to implant the chondrocytes into the cartilage defect under a small flap of tissue that is sewn into place. The flap of tissue holds the cells in place until they heal to the surrounding tissues and become hyaline cartilage. The second procedure is typically done as an open procedure. The result of this procedure is repair of the cartilage defect with nearly normal hyaline-like cartilage.
The typical patient considered for this procedure is a young, active individual with a isolated traumatic cartilage injury. The main disadvantage of this procedure is it requires two operations. The postoperative rehabilitation involves a period of non-weight bearing with crutches (8 weeks) and the use of a continuous passive motion machine (CPM).