Technique for “sandwich” implantation of autologous chondrocytes. A, Osteochondral defect and bone defect are similar. B, High-speed burr, usually 8 mm in diameter, is used to remove all subchondral sclerotic bone back to healthy-appearing spongy bone. Base is drilled multiple times with a Kirschner wire to enhance the blood supply to the grafting site. A 3-mm burr is used to undermine the subchondral bone to secure the membrane when it is glued to graft with gentle pressure and covered by a neutral patty as the tourniquet is released and knee is brought into full extension. Neutral patty is removed, defect is separated and dry from underlying marrow space and bone graft. C, Second membrane is sutured to surface and sealed with fibrin glue. Cultured chondrocytes are then injected or “sandwiched” between two membranes.