Hypothermic Storage and Cryopreservation of Cartilage

Osteochondral autografts of femoral condyles in dogs were frozen at different cooling velocities after exposure to either glycerol or dimethyl sulfoxide to determine the freezing regimen best suited for preservation of intact cartilage. Autografts were also subjected to hypothermic storage in tissue culture media for ascertainment of how long they can be stored under these conditions. Autografts maintained in vitro under various conditions of storage were examined after transplantation. Autografts were chosen for this portion of the investigation in order to study the effects of storage uncomplicated by immunologic interactions. No differences were found between the cryoprotective actions of glycerol and dimethyl sulfoxide. The freezing rate that produced the least damage in the cartilage was Z"/min. Cartilage survived ten days of hypothermic storage in tissue culture Cryopreservation of articular cartilage is still a subject of some controversy. Suspensions of isolated chondrocytes, after exposure to various cryoprotective agents and selection of optimum cooling rates, have been frozen with good results. However, attempts at cryopreserving intact cartilage on osteoarticular segments of bone have not met with the same Jimenez and Brighton6 have extensively studied in v i m preservation of sagittal slices of rabbit cartilage. These investigators reported that cartilage slices stored in tissue culture medium for seven, 21, and 60 days at 4" and 21" failed to incorporate "S. In medium. Allografts frozen by the standard method of glycerolization and c o o h g at l"/min were also studied. These showed eventual loss of chondrocytes and conversion of hyaline cartilage to fibrocartilage. contrast, cartilage explants stored in the same